Thom hi thanks for the quick reply

Following your thoughts I changed the text-box properties to decimal to two pleaces, each and every value returned a whole number

I cast the column that calls the function as an int (although I know the function returns integer values) and altered the procedure. No change, still odd values in the text-box

I created two further data-sets; both call the function and pass it two dates

In both cases in Query Designer the right result is returned but on the report face one value is over stated by a day and the other understated by a day