Hi Mihail,
I tried both ways with yours and JDraws: Using a test date of 3/7/2014 the 90 day retest date results is 6/5/2014
=IIf(DateDiff("d",[Retest Date],[Test Date])<=90,[Test Date]-[Retest Date]-90,0) returns -180 days passed
=IIf(DateDiff("d",[Retest Date],[Test Date])>=90,[Test...