Gap income and short plan year

[Guest mo again]

Plan specifies that gap income is to be attributed to corrective amounts using safe harbor 10% method. The plan year being tested is a short one of three months (10/1/99-12/31/99), so the dollar amounts of both the excess contributions and the attributable income for the plan year are low. Taking 10% of that amount per gap month seems to produce an artifically low gap income amount, and does not jive with what I have always thought was the concept of the safe harbor formula. However I do not find anything requiring any adjustment for a short plan year. Any thoughts?