google sheets – Using INDEX to move a value, but also do an operation on it?

I’ve built a crop planning calendar in which I enter the date I want a crop to be ready in one sheet, and it is automatically populated in the following sheet using INDEX.

The goal is to enter the date I want the crop to be ready in the first sheet, and the formula in the second sheet “reverse” dates back to the date I need to plant it (which is an earlier date), using:

``````=IF(U\$3+MROUND((\$BH4+\$BG4)/7,1)>=53, "", IF(\$C4="Baby", INDEX('TP Bedft'!\$D4:\$BC4,1,U\$3+MROUND((\$BG4)/7,1)), INDEX('TP Bedft'!\$D4:\$BC4,1,U\$3+MROUND((\$BH4)/7,1))))
``````

On the third sheet is the day on which I’m supposed to seed it in the greenhouse (which is even earlier). However, I not only want the data to move to the right cell (week), but I also want to do an operation on that number to convert it to, in this case, the number of trays to be seeded. Right now I’m using:

``````=IF('TP Schedule'!U4="","", MROUND('TP Schedule'!U4*\$BF4*\$BH4/\$BG4,0.5))
``````

This changes the number from the second sheet to “# trays”, but how do I do that calculation AND move it to the right cell using INDEX within the same sheet?