How it's calculated: Price ÷ (Qty × unit size) gives price per base unit. Yield % is the usable share you can actually measure or predict — under 100% for trim loss, over 100% for something that gains weight when cooked (dry noodles or rice absorbing water). Wastage % is a buffer on top for what you can't predict — shrinkage, moisture loss. Both are set per item. Inflation is set once, above the table, and applies as a single blanket rate to every item's True Cost — it's a forward buffer for supplier price rises, not something that varies item to item.
For a purchase that's pre-divided rather than sold by weight — a pack of noodles that makes 8 portions, a whole chicken cut into 8 pieces — pick the portion or piece unit, and set Qty to the portion/piece count rather than a weight.