The speed doesnt drop with each service… they use different frequency wave lengths for each of the Voice , Video , and Data streams. With many tests to prove that no backscatter is returned, you get a good clean signal for each one. Now they have it mapped for a set level of users allowed on each fiber due to current light color streams that allow distinct variation and can be seperated at the wave division multiplexers. They run 512 fiber pair to each local area to be serviced that is fusion spliced to the run in the CO. Now the fiber size and internal construction is the same in the CO as the drop loop outside your home. Key difference is the protective jacket , this fiber can basicly do what ever speeds that they throw at it right now. So for you to have an out dated service really wont happen. Like as of now … they are looking to ramp up speeds (same cost as before but faster service). For example taking the 30 meg to 50 meg at the drop of a command line. This system rocks…
Oh … We run on a OC192 and looking to up the speeds to what is working out to a OC290 
. Also are set limit of users is still about the range of comcasts (around 30) but with 1000% the technology and the unlimited range up upgrades without large costs. This means no crazy bill increases like comcast likes to throw out there haha (used to have them so i know).
But again no one will guarantee speed to a kb unless you pay for a speed service. AKA T1 , OC3 , VT12 ect… But our speeds so far even with a loaded card seem to be about tits on the money with your 5,10,15 service.
The video side is on the move in PA finally now too … I would say look for it to come out next year.