How does the wheat slab system work?

Each quality parameter's rebate % is a weight multiplier (×) applied marginally to the slice above each threshold: slab `above X% × b` means multiplier b only applies to the width between X and the next slab's threshold. The total weight % is valued in ₹/quintal at the base rate as a quality claim. Every parameter also has an explicit reject ceiling. HL is reverse-direction — lower HL is worse, so its slabs cover the range below the accept threshold and the reject fires below it. KB (Karnal Bunt) and SMB (mudball) are pure accept/reject gates. Claims accumulate; bardana is converted to ₹/quintal; cash discount is applied LAST on the net payable.

What are the default slabs (Spec A vs Spec B)?

Defaults match the stricter mill spec (Spec A): HL accept 78 (×0.5 above 77.5, reject 7%); moisture 10% (×1 above 10%, ×1.5 above 12%, reject >13%); potia 8% (×0.5 above 8%, ×1 above 12%, reject >15%); FM+OFG 1% (×1 above 1%, reject >2%); red grain and black tip 2% (×0.5 above 2%, reject >3%); KB reject >0.10%; SMB reject >0.20%. The looser Spec B uses HL ≥77 (no rebate band, reject 8%), potia allow 10% (×0.25 above 10%, reject >15%) — edit the slabs above to match.

Wheat quality parity calculator — India

Q: Can I match a specific buyer's notice?

Yes. Every allowance, slab, rebate % and reject threshold is editable and remembered on your device — set them to your buyer's published terms.

Price a wheat lot on the Indian slab spec: stepped price rebates for HL, BIS (broken+immature+shrivelled), moisture, potia, FM+OFG, red grain and black tip — plus pure accept/reject gates for KB (Karnal Bunt) and SMB (mudball). Then cash discount and bardana to a net ₹/quintal and lot value. Every allowance, slab and rebate % editable to your buyer's notice.

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What it does

Each parameter's "rebate %" is treated as a weight multiplier (×) applied marginally to the slice above each threshold — same engine as the soybean moisture/FM model. For BIS, moisture, potia, FM+OFG, red grain and black tip the slab above X% × b means multiplier b only applies to the width between X and the next slab's threshold. HL is the only reverse-direction parameter — lower HL is worse, so its slabs cover the range below the accept threshold. KB and SMB are pure accept/reject gates with no rebate band. The total weight % is valued in ₹/quintal at the base rate as a quality claim; claims accumulate; bardana is converted to ₹/quintal using the bag weight; cash discount is applied LAST on the net payable (never on the gross rate).

The formula

For each upward-bad parameter (banded): wt% = Σ over slabs of (slice width × multiplier b), where slab i's slice is (slab[i].a, slab[i+1].a] intersected with (allowance, reading]; the top slab runs to ∞.
For HL (mirror): wt% = Σ over slabs of (slice width × b), where slab i's slice is below slab[i−1].a (or accept for the topmost) and above max(slab[i].a, reading).
claim ₹/qtl = − base rate × wt% ÷ 100 (per parameter).
bardana ₹/qtl = (100 ÷ bag kg) × ₹/bag (deducted).
net payable = base rate − Σ claims − bardana.
cash discount ₹/qtl = − net payable × CD% ÷ 100 (applied LAST on net payable).
net realization = net payable + cash discount; lot value = net realization × quantity.

Worked example

Clean Spec-A lot at base ₹2,500/qtl (HL 78, BIS 3%, moisture 10%, potia 8%, FM+OFG 1%, red grain 2%, black tip 2%, KB 0%, SMB 0%, 50 kg bags, ₹20 bardana):

Every reading is at the allowance → all quality claims ₹0
Bardana = (100 ÷ 50) × 20 = −₹40/qtl
Net realization = 2,500 − 40 = ₹2,460/quintal · within spec ✓

Off-spec lot — HL 77.6, BIS 5%, moisture 11.5%, potia 11%, FM+OFG 1.5%:

HL: (78 − 77.6) × 0.5 = 0.20% wt → −₹5/qtl
BIS: (5 − 3) × 0.5 = 1.00% wt → −₹25/qtl
Moisture: (11.5 − 10) × 1.0 = 1.50% wt → −₹37.50/qtl (reading is inside the first slab; second slab not reached)
Potia: (11 − 8) × 0.5 = 1.50% wt → −₹37.50/qtl
FM+OFG: (1.5 − 1) × 1.0 = 0.50% wt → −₹12.50/qtl
Red grain & black tip at allowance → ₹0
Bardana → −₹40/qtl
Net realization = 2,500 − 117.50 − 40 = ₹2,342.50/quintal

Moisture 12.5% would cross into the second slab: (12 − 10) × 1.0 + (12.5 − 12) × 1.5 = 2.75% wt → −₹68.75/qtl (marginal banding — only the slice above 12% gets the steeper 1.5× multiplier).

Spec A vs Spec B — what's different?

Spec A (default, stricter mill grade) and Spec B (looser standard) share most parameters. The differences are HL, BIS and potia: Spec B uses HL ≥77 (no rebate band, reject <77); BIS allow 4% (×0.25 above 4%, reject >8%); potia allow 10% (×0.25 above 10%, reject >15%). Edit the slabs in the Quality parameters table above to match.

Can I match a specific buyer's notice?

Yes — every allowance, slab, rebate % and reject threshold is editable and remembered on your device.

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