I have no idea what you are saying because splitthreshold 24k or whatever I type in console gives the same value back:

splitthreshold 15000
22:36:01

{
"amount" : 2500.00000000
}
22:36:25

splitthreshold 240000
22:36:25

{
"amount" : 2500.00000000
}
And I cant find any proper documentation in the wiki what this does exactly. Maybe anyone want to link me or explain to me how this works.
I'm used to seeing the threshold of a point where if you can create 2x blocks of the value entered then it would split, else stay as one block... it appears that what actually happens is when it reaches ≥2500 hbn then it will split into two "equal"ish blocks.