We have multiple products with subscription level access. This is on purpose.
However, we have had continuing problems with people NOT seeing more than one of their products-by-subscription.
To circumvent this, we've made more work for ourselves by removing the subscription and then have to manually contact each person with the access point for the other information.
There does not seem to be a way for people to have more than one level without causing problems. We get redirect loops on the permissions page most commonly. NOTHING has worked to fix it.
When I brought up a similar, related issues months ago, there was no support for it.