The only problem I see is the "if necessary" part. You will likely get troubles selecting your load in split vs non-split workouts. E.g., if you got your reps in a split work-out, it doesn't necessarily mean you will be able to do the same in the next, non-split workout, more so to increase the weight.
If split workouts are rare, I'd probably just won't increase weight after them for the next (non-split) workout. If non-split workouts are rare I'd use exact weight from previous split workout, or rather split them as well. Most tricky to program is random 50/50 distribution.
From the POV of progress, splitting all the workouts is probably the best option, me thinks.