BI Publisher Data Field formulas

Summary:

Hello Oracle folks,

Maybe someone knows the solution to below: can someone help how to achieve adding two summarized data field in BIP Layout?

I have 2 fields that i have to display as summation.

total invoice, total revaluation - i was able to add them successfully.

now customer wants to display total revaluated invoice amount = sum(total invoice) + sum(revaluation) or total sum(invoice + revaulation).

what kind of formula is needed to achieve this? Is this possible at all? Thank you:

Content (required):

Tried using nested functions but did not work. Pls advise.

I also tried below approach but its still not adding up.