Is it possible to split karma koins?

So I havn't actually bought a physical Karma Koin in awhile so how exactly do you do this? When you go to redeem the card the first thing it has you do is enter the code. After that is there a bunch of buttons for what value you want to take off the card? And if so what are the value increments? I ask this because I never remember being prompted an option to do this. Thanks.

Enter code > select amount (if $10 code, $1, $5 or $10) > hit charge, the specified amount is taken from the card.

I think the amounts for $25 cards are $1, $5, $10, $20, or $25, but I'm not sure exactly. I usually buy $10 ones.