IP Integrated Planning FOX Variable usage

I am porting an application from BPS to IP.

One of the planning functions is a FOX formula function.

I copied the function parameter group (code) to the IP function.

In the program checker I am eceiving an error concerning the use of VARI function.

In BPS I had created a variable that contained singel values of fiscal year period (0FISCPER) for fifty years. I used this "vector" to establish the relationships between various periods for use in my algorithims.

Can I access and use the existing BPS variable in IP?

If not, how do I create a variable in IP to perform the same task?

If the VARI and VARV functions are available, what variables do they address?

Also, if someone has a better way of calculating differences between fiscal year periods, please let me know.

I thank you for your answers.

Andy