Splitting powders is an art as much as a science. When anything granular is sampled for testing certain "splitting" tools and techniques are used. I don't split powders, the manufacturers have done this for me. I just mix developers using pure water and decant into full bottles.
The folks who manufacture these powders use ingredients of appropriate size and condition that eases manufacturing and packaging (where the powder splitting occurs)
As the NASA scientist said to the brain surgeon.
Your job is not exactly rocket science!
And so it goes; there is too much mystique around black and white photography nowadays.
I remember some 40 years ago when the magazine Darkroom Photography tested various premium black and white papers, comparing max D Max etc.
They announced the surprise of the pack was Freestyles Arista Classic that just beat out Ilfords Galerie!
Turned out that Arista Classic was just re packaged Galerie.
When some use caffeine to develop films I suspect the additional gram or minus makes little difference?
Splitting the XTOL rather than mixing the lot and making 5 mixes still makes sense to me particularly as MY results were more reliable.