XIRR - Automating the date range

[WTM]

Does anyone have advice on what functions I can use to automate the
date range on an XIRR calculation?

I'm using offset to seek out the values I want, but I can't use the
same method to provide the date range, because XIRR won't accept the
format of the dates provided by offset (#Value! error).

The dates are one row above the values, how can I get this information
into XIRR?

Thanks