Hi Tigertc,
Sorry to disappoint you, but it is a rather old trick from many moons ago, you have just rediscovered it.
We used to make our own perspex cement and plastic filler in exactly the same way as you have discovered.
It seems that modellers nowadays want it to come in a tube or tub, and don't seem to realise that you can play around with things to get just what you want.
Well done anyway.
John