I have had he plan drop hundreds of times for me, and I can tell you that magic find doesn't really affect the rate at which the plan drops, but the biggest thing that does is the skill level you play on. Allthough you can get it to drop on any skill, Due to the plan being of lower level. (Higher level plans for the staff are bought, not found) it's more likely you will get it drop on normal. I have had it drop on all skill levels, but the drop rate on normal is much higher than any other.

I have had the plan drop hundreds of times for me, and I can tell you that magic find doesn't really affect the rate at which the plan drops. The biggest thing that does is the skill level you play on. Although you can get it to drop on any skill, due to the plan being of lower level (higher level plans for the staff are bought, not found), it's more likely you will get it to drop on normal. I have had it drop on all skill levels, but the drop rate on normal is much higher than any other.