Horizontal vs vertical a Big Flash issue?!

Someone must have encountereed the problem i’m experiencing right now.
I’v made a flash script for to duplicate lines and then move them.
If i run the script horizontal (from left to right) it runs half as slow as the vertical one (same script, objects turned -90 dergrees). Can anyone explain this, it’s quite urgent.
SOMEONE PLEAse: IS THIS A KNOWN ISSUE OR NEW TO ALL???

is everyone afraid to admit
they don’t know or is it just me