The Only time I ever purchased 'H' fares were when they were the lowest fare available and I knew that space was very limited. Otherwise I would simply purchase the lowest fare that was available.

Now if when Im purchasing the tkt Im told that BF is available for a Confirmed Upgrade there & then, Ill do some quick Math and see how much the lowest plus the Fees & miles would come to vis an "H". If an "H" is slightly more Id go that way to get the 150% on the EQMs.

Now if an Up cant be confirmed, Id NEVER purchase an "H" as most likely it wont ever be available.