Request: when the engine is about to assign a cost basis that is near zero on a large quantity, or far above market value on a dust quantity, flag the row for review instead of committing it silently. A simple bound against the asset's market value on that day catches both directions.

Why it matters: in my account three lending withdrawals on Sui (haSUI and vSUI, September 2024) received a basis of $0.01 on five-figure quantities, while other lots of the same asset in the same wallet minutes earlier kept a basis near $1.03 per unit. That created about $43,700 of gains that do not exist. The reverse also happened: $1,014.52 of basis was assigned to a 0.0001 SOL leg and immediately realized as a loss. A likely contributor on Sui is that the asset labeled VSUI is CERT on chain, which may break lot matching.

Who benefits: users see the rows that need attention before filing instead of finding phantom gains later; the same check would catch counter-leg pricing on tokens with no price feed.