Yes, I can see a difficulty. The '90-day' rule requires at least 3 takeoffs and landings to have been carried out within the preceding 90 days in order that passengers may be carried. There's no provision made as far as I can tell, unless you use the 'remarks' column, to record the number of t/o & landings, just the date, location and times of each flight - not the same thing at all! So if you choose to do 3 circuits to meet the qualification, the only way you can annotate this is to say so in the remarks, not very scientific, really. The only way to be absolutely sure, is to conduct 3 entirely separate flights within the past 90 days.
Now, we'll start the old debate about whether or not 3 touch-and-go's counts as 3 takeoffs and landings...
Cheers,
TheOddOne