How can I do a calculation in SAC story to sum values over fiscal periods?

[SB1512]

I have a model which brings data for past periods until current period. I have another model that brings data for current period. I am displaying amount for current period in a table and next to it I want the YTD (sum of amounts from all previous periods fetched in the YTD model. I am using classic mode and blended the two models. The issue is my YTD sum looks very large. What best calculation can I use on story to get proper values. see attached details . 

 fiscal period 8,9 are referring to Feb, March 2025

Any pointers would be very helpful

[William_Yu]

Is your model acquired model or live model? If it's acquired model, why you need to have periodic value and YTD value in the two different models? You can put them into same model, or you can just caluclated YTD value on the fly with periodic value.