Question about upgrading

I'm getting ready to upgrade to a CS5 Premium Design suite through a third party vendor but before I do, I have a quick question I'm hoping someone can answer.

While I have individual programs, my best price will be by upgrading from Macromedia Studio 8. I see that I can upgrade for $799. However, looking at 3rd party sites, their upgrade packages at that price are for upgrading from CS3/CS4. They offer no other paths.

My question is this, if I buy one of those, will my upgrade work? I'm guessing I'll be fine, but just thought I'd check. I would have asked Adobe directly, but I can't seem to find any presales contact info.