Things don't tend to change this dramatically overnight. That's what I still find odd...
If you need to limit something to 6.25% then something is running out of capacity. All I'm asking is what that'd be...
No, the shaping has no correlation to the capacity at all.
Shaping is applied to make sure that realtime services aren't degraded and it's there due to demand on the network. If we didn't have shaping in place non-essential traffic would be contending directly with browsing or a realtime service. If there was zero shaping what we'd see is an almost instant latency spike and have almost all services degraded on our network.