"YMMV" is just a play on words from a statement often found (at one time, maybe not anymore) on car advertisements and window stickers. You know how they state the official EPA gas mileage ratings? Often there would be an asterisk with fine print stating "your mileage may vary" or "actual mileage may vary depending on driving habits, etc, etc". At some point it became an internet acronym meaning that the poster can't guarantee you wil have success, or the same results, etc.

The poster just means that some people may get approved in similar circumstances, others may not. Hence, while advising you to try, the poster is advising that they can't guarantee you will have favorable results.

You'll find a lot of gray area things in FF world that one person will get outcome A, another outcome B, and still another outcome C. Sometimes there doesn't seem to be any rhyme nor reason that we can discern from the information available. In those cases it's up to each of us to either give it a go, or not, and see what happens.