Questions about PRIOLOSEC OTC

I hear that for LPR you are supposed to take 2 PPI per day (assuming you believe in meds).  I looked at the lable for prilosec and saw that the directions indicate taking prilosec for 7 days once every FOUR months...
 
Is prilosec OTC different from other Prescribed PPI's or do they just make those directions to cover themselves.
but you take 1 a day for more than the 7 days that it says on the box?  Another reason i ask is because its so much cheaper...nexium is $80 for a 2 month supply....whereas prilosec OTC would be like ... $20..