If you are adding them to a subpage they will show up on every page that subpage is on. So you have to options:

1. Write PeopleCode to make the fields visible only on the page that the fields were intended to.
2. Put your 2 new custom fields on the page itself and not the subpage.

I would go with option 2 as this will result in less customization, less affected objects and so results in a smaller testing effort.

Thanks Lepa