I'm all for fixing the weird inconsistencies with bucket volumes.
All potential issues I can think of can be fixed by each mod dev by using other display methods.
1/9th of a bucket or 1 Ingot's worth of fluid is easier to work with than the two split systems, where machines tend to use round numbers if the fluid is not a metal or the ingot values every time it can be converted into an item.
However, what do we call 1/1296th of a bucket? Mini Buckets?