There are two ways to look at this:
1- My players don't abuse it so it doesn't matter.
2- What should the general rule be to keep this from being abused outside of the Utopia that is our own game...
I think 1 is great, but since this is a message board for the whole world 2 certainly has to be considered. Which leads to 2 possible decisions.
1- House rule it so that the "statis" does not affect spell durations.
2- Or rule that it does and increase price by at least 10x.
The current cost is no where near balanced with ruling that the statis affects spell duration, even if there's nothing in the rules which prohibits it.