pretty much same as HBN.
In order for a stake to split, it has be over your threshold. Your wallet will combine smaller UXTOs up to the combine threshold
How come when you issue the following commands it it returns a figure other than the one that is entered for the following example:
Comnand issued
splitthreshold 10000
combinethreshold 10000
returned result
12:10:49

splitthreshold 10000
12:10:49

{
"amount" : 325.59000000
}
12:11:26

combinethreshold 10000
12:11:26

{
"amount" : 651.18000000
}
Max allowed amount depends on total wallet balance.