Hi all. I have a question regarding the true ISO of the film I use...

I have read many times that people who shoot with Arista EDU Ultra 100 actually rate it at about ISO 50, and sometimes ISO 32.

How do I actually treat a 100 speed film as if it were ISO 50? In my mind I have thought about it in the following ways:

Do I just double my exposure times and develop normally?
Do I expose regularly and halve the developing time or the developer dilution?
Do I double the exposure AND change the development time?

I've also wondered if there are actually multiple correct approaches just like there are multiple combinations of aperture and f/stop for the same light reading...Any info would be much appreciated.

Thanks much,