Jon,
First of all, if you were around 4 years ago around this time when butter was $4 a pound you would be raising prices more than $0.10 a plate. Maybe you were and you didn't for some reason, which brings me to my next point.
Second of all, even if you did raise prices $0.10 a plate your customers might go somewhere else. I'll repeat a small business lesson for you. Customers should not have to bear YOUR cost of doing business. True prices are set more by market demand than by your food cost.
You know what, do what you want. If you believe that eating minute quantities of free fatty acids will kill you then by all means don't do it. The problem is that overzealous health nuts use this information to spread fear among the general populous in order to further their irrational cause. The article you point to is titled to imply that for some reason the makers of margarine are out to fool the world. There is no margarine "hoax" as the article implies. Nobody is trying to kill us with tran-fats.
I cannot stress enough the importance of placing things in a proper context. Once again, you're not putting the stuff on a stick and eating it for dinner. If you're eating enough to make you worried then you should be worried about other things as well.
Kuan