Math Macro Help for 3.5 Jump spell

So the Jump spell says "The subject gets a +10 enhancement bonus on Jump checks. The enhancement bonus increases to +20 at caster level 5th, and to +30 (the maximum) at caster level 9th." I'm making spell macros and I was wondering if there was some way to derive the bonus from caster level in a macro. I tried a bunch of things with floor and ceil functions, but could never get it right. Level 4 always seemed to give +20 when it should be +10 or level 5 would do the reverse. This is more for the challenge than anything else. The bonuses are pretty simple to figure out and apply in play. If I really needed it to be generated automatically, I could do a rollable table or the API to get what I want, but something tells me there is a way to do it in a macro and I just can't see it. Maybe I have been working on this too long... :-) Thanks to anyone who can satisfy my curiosity!

[[10 + {floor(@{caster_level} / 5), 1}kl1 * 10 + {floor(@caster_level} / 9), 1}kl1 * 10]] should do. At levels 1-4, that'll be 10 + 0 + 0, at level 5-8 it'll be 10 + 10 + 0, and at level 9+ it'll be 10 + 10 + 10. You can add nested inline rolls to clean up the output if you like.

[[ [[[[ceil((5 - ?{CL})/100)]]d1* 10 ]] + [[[[ceil((9*floor(?{CL}/5) - ?{CL}*floor(?{CL}/5))/100)]]d1* 20 ]] + [[ceil([[floor(?{CL}/9)]]/100)* 30 ]] ]]

Wow! Thanks to you both for the quick response! I will put these into my Macro text file and parse them out to add to my math knowledge. Many thanks again! :-)