The "Pension Packet" as NARA calls it, gives you 8 documents--and not necessarily the best ones from a genealogical standpoint. It's all a matter of whether you really want everything that is in the file or not. The 1812 pension files are not large, so it's more of an issue with Civil War pensions. I can tell you, with a "pension packet" you would not get the more personal pieces in the file, if they exist. You would probably not get a copy of the original marriage certificate if it was sent in, nor would you get copies of original handwritten letters. Of course there's no way to know what's in a file ahead of time when you order from NARA. Since 1812 pension files are not usually very large (maybe 30-50 copies each), it may or may not be worth it to you to order the whole file. It's more of an issue with Civil War pensions, which might be 300+ documents. For very large pension files, even when you order "whole file", NARA will not copy all of a file if it involves several hundred copies. They figure you won't know what's missing anyway.
When I go after an 1812 soldier, I like to get the service record, pension file, bounty land file (if it wasn't filed in with the pension), and the surrendered warrant. If ordering from NARA, all this would cost you close to $100 (and NARA doesn't even list a price for the surrendered warrant, because they are difficult to copy and they don't want people to know about them)! If you hire an independent researcher, they can probably do it all for a lot less.
Your other option would be to wait a few years and maybe Fold3 will get up to the "P" surnames in their 1812 pensions database and you can look at it there.
Best wishes.