XLOOKUP using other formula

Hi

I have a lot of data and I'm using the xlookup function. I want to know exactly what it is looking for.

My data has the date and time spread over a lot of columns so I've had to use formulas to provide it in one cell (e.g. =DATE(a,b,c)+TIME(d,e,f)), my xlookup formula uses a cell which contains this formula as the lookup value and searches a column in an array which also holds multiplies of this formula. 

Is the xlookup function matching the formula or the values because they are very different? If it is matching the formula is there a way of getting it to match the values? 

Thank you

K