Capstone Billing Simulation: Three RA Bills

A BOQ earns its keep on billing day. Running-account (RA) bills are where measured work becomes money — and where weak measurement records become disputes. In this lesson the Anand Villa contract runs its full billing cycle: three RA bills over ten months, with retention, GST treatment, one deviation, one extra item, and a final bill that reconciles to the rupee.

Contract terms (typical for private residential item-rate work — always read your own contract): contract value ₹29,20,036 as per BOQ; payment against joint measurements recorded in the measurement book (MB); retention 5 percent of gross work value, half released at virtual completion and half after a 12-month defects liability period; no mobilization advance; GST as applicable, shown separately. Quantities are provisional — payment follows measured work at BOQ rates.

The billing arithmetic below uses one discipline worth copying: retention is always computed on the cumulative gross and the previous holding subtracted. Bill-by-bill rounding then never drifts.

RA-1 — end of month 2 (substructure done, GF columns cast)

Cumulative measured quantities and amounts:

Two things to notice. GST is charged on the full taxable work value — retention is money withheld from payment, not a reduction of the taxable value (commonly applied practice; confirm treatment with your CA and contract). And the 13.0 cum of RCC is traceable: substructure 10.46 + ground-floor columns 2.48 + part of the stair base — the MB pages list each member.

At this point the project has certified 9.2 percent of its final value. Cross-check against the Lesson 3 budget: stage 1 (₹2,16,048) plus early frame work — the S-curve is exactly on the slow early climb every project shows.

RA-2 — end of month 5 (frame complete, masonry underway)

Cumulative certified: 37.0 percent of final value at month 5 — the steep middle of the S-curve, where the frame's big-ticket items (RCC, steel, formwork: ₹8.65 lakh together) land in a single bill. This is why cash-flow planning (Module 5) matters: the owner needed nearly ₹9.3 lakh liquid this month, three times the RA-1 outflow.

The other side of the table has a cash cycle too. The thekedar pays his naka labour every week and his material dealers on 30-45 day credit; your RA bill is his only inflow. Certify a correct bill 20 days late and he bridges the gap at 2-3 percent per month from an informal lender — a cost he will quietly price into your next rate negotiation, or recover by stretching the work. Prompt certification of measured work is not generosity; it is the cheapest construction finance on the project. (The discipline cuts both ways: prompt for measured work, immovable on unmeasured claims.)

Between RA-2 and the final bill: one deviation, one extra item

Deviation (existing item, quantity changed): final vitrified flooring measured 133.8 sqm against the BOQ's 130. In an item-rate contract the measured quantity simply pays at the BOQ rate: +3.8 sqm x 1,350 = +₹5,130. No new rate needed.

Extra item (not in BOQ): the owner adds an overhead-tank pedestal and platform. No BOQ rate exists, so a rate analysis is prepared and approved before execution: RCC 2.1 cum (17,220) + steel 160 kg (12,480) + formwork 12 sqm (5,040) = +₹34,740.

Final contract value = 29,20,036 + 5,130 + 34,740 = ₹29,59,906. Both changes fit inside the ₹1,46,000 contingency (using ₹39,870 of it) — the budget holds without revision.

RA-3 — final bill, end of month 10

A RERA-era aside on that defects liability line: our private contract holds the thekedar for 12 months through retention. A RERA-registered developer faces a five-year defect liability to buyers under the Act — which is exactly why developer-side QS teams preserve this same trail (MB pages, pour cards, cube-test registers, bill files) for years, and why a QS who keeps clean records is employable on both sides of the table.

The reconciliation that closes a project. Total payments 3,08,892 + 9,28,375 + 21,07,427 = 33,44,694; add both retention releases (1,47,995) = 34,92,689. Cross-check independently: final work value 29,59,906 + total GST (49,204 + 1,47,883 + 3,35,696 = 5,32,783) = 34,92,689. The two paths meet to the rupee — that is what "the books close" means. (And 5,32,783 is 18 percent of 29,59,906, allowing rupee rounding.)

Budget verdict: final value ₹29,59,906 against the sanctioned ₹30,66,036 — ₹1,06,130 under budget, with the contingency absorbing both changes.

A note on deductions we did not simulate: a salaried individual building a personal house generally has no TDS obligation under section 194C, and section 194M applies only above ₹50 lakh of contract payments in a year (rate 2 percent as of recent amendments) — below our contract size. Business owners, companies and government works face different TDS and GST-TDS regimes. All of this is commonly applied practice, not tax advice — confirm with a CA before finalizing any bill format.

Common billing mistakes

How this lesson protects your bill: every rupee above traces to a jointly signed MB page and a BOQ rate — which means either party can hand this file to an engineer-arbitrator, a court, or (on developer projects) a RERA authority and win on paper alone. The party that billed "as per site" with no measurements is the party that loses. With that lens, the classic failures:

• Retention on the net or on GST-inclusive figures. Fix the base in the contract (here: gross work value, excluding GST) and compute cumulatively.
• Billing unapproved extra items. The pedestal was billable only because its rate analysis was approved before casting. Work first, approval later is how contractors finance disputes.
• No cumulative-minus-previous structure. Bills that measure "this month's work" directly, instead of cumulative minus previously certified, double-pay or miss work at every stage boundary.
• Final bill without reconciliation. If payments + retention do not equal value + GST, the error compounds silently — find it while the parties still answer your calls.

One more artifact remains: proving the whole trail hangs together, and planning what you do with this skill next.