Difference between IG & AG solar blanket?

I need to replace the solar blanket on my 15x24 AG. I always see mailings that list different blankets and pricing for AG & IG of the same grade and thickness. My question is -If for example both are 12 mil thick and the same grade - what is the difference between the AG & IG solar blanket. Is it only that IG 16x24 has squared conners, where the AG 16x24 is oval?

BJ's has what seems to be a decent blanket (and price), but it's an IG and larger than I need. I am not opposed to trimming if this is the case.
Thanks, Harry D.

PS. For those of you who are thinking of one and have doubts - I have used a SBlanket for 18 yrs and think they work great (in east coast NJ area).

I've looked at them in the stores and strongly believe that the only difference is price and marketing. They seem to think if you own an IG you can aford to pay more :)

Similar to pool store chemicals versus supermarket chemicals - all marketing and price.