The best way I can put it is in terms of tiers. Lets say there are three tiers:
Tier 1 - was up to 50Mb, now up to 100Mb
Tier 2 - was up to 100Mb, now up to 200Mb
Tier 3 - was up to 200Mb, now up to 350Mb
From what you have said you were originally on tier 2, but have since downgraded to tier 1 to save money. As a result of the speed being increased on each tier at no extra cost, you have ended up back on the same speed you originally had but at a lower cost.