I'm wondering if it's possible to put the ROUNDTONUMBER function around an equation rather than just a number?

For example:

I am using the following script to derive a number, which works nicely drawing pieces of information from early in the survey and generating a number for use in an ACBC. However the numbers it generates are often awkward in the sense that they aren't rounded. Like 80,567. where I'd rather the respondent see 80,500 (rounding to the nearest 500) etc. is this possible?

[% (((WPSM5Price+WPSM6Price+WPSM7Price+WPSM8Price)/4)*.7)+ HowManyRoomsHouse%]

I haven't been able to make it work so far...

Any help would be greatly appreciated...