Help with formula

I'm moving from a spreadsheet to Ninox, so have to translate a lot of the formulas into Ninox.

So far, with some help from Joerg, i've been able to tackle quite a few, but i've come to a formula i'm not really sure how to move over.

What i want to do could be described in the following way: if any of Field A is >= the most recent value of Field B,  then sum the values of Field C in those rows (where Field A is >= Field B).

All these fields (columns) are in the same table.

I've come up with an initial version of this, but i doubt it's right. Sticking with the A, B, C field names:

if A >= max(B) then sum(C) end