"where the signdata appends, rather than overwrites the previous entries" - it's possible with REC like:
%VALUE%+[TIME].[$TIM1$.02],TIME=$TIM1$.02
But I absolutely not recommend this approach!
The correct idea is to keep data from BW as is in some AUDITTRAIL member and the script will generate YTD result in another AUDITTRAIL member.
Vadim
P.S. Slightly unclear what do you mean by "signdata appends"