Tony, those look great! Each of your other examples looks beautiful and smooth without any of the obvious stepping in the original FX.
BlurMaster is a transition pack and has a standalone tool like most other Pixelan plug-ins. It does have keyframes available there, although you really only need a starting and ending one to have a smooth gradiation.
I also have the CreativeEase (Version 3) BlurPro FX and it has essentially the same tool as BlurMaster. Keyframes aren't greyed out on my system, so it's actually a better choice for OP's issue since you can keyframe a single clip without having to split the clip in two, like this:
There are also animated presets so you don't need any keyframes, just place the FX on the track below the clip where it's needed.
All in all, lots of choices are a good thing here