Synonyms for Allowance (same or very similar meaning)
WordNet sense 1 (a reserve fund created by a charge against profits in order to provide for changes in the value of a company's assets):
valuation reserve, allowance account, valuation account
WordNet sense 2 (an amount added or deducted on the basis of qualifying circumstances):
adjustment
WordNet sense 3 (a permissible difference; allowing some freedom to move within limits):
leeway, margin, tolerance, margin
From the ODE community, based on WordNet
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