That's not partigyle, that's splitting a 10g batch. It'll work fine if that is what you are asking. It's also a great time to experiment with different hop schedules or yeasts.
You say "run off into separate kettles", but I think you know you need to run off into one vessel, then split, to make sure it's all the same gravity.
I think it is odd you get better efficiency from more grain. Must be you are sparging more, which will definitively improve efficiency.
Now there's some take delight in the carriages a rolling
and others take delight in the hurling and the bowling
but I take delight in the juice of the barley
and courting pretty fair maids in the morning bright and early