Oh no, I did get that. Hence my answer. There is no way to "Add" space to an SD card. Not unless you remove items off the card (say other files, that are not related to the game). However, that doesn't mean moving them off the card will give you enough room. There may just not be enough room on the card for the update, no matter what you do. If that is the case, it would require you have the game on a larger (more gigs) card.
Because, let's say the card is 16gb, which is never actually 16 free, and you said there is 7.35 free, that means 8.65 is being used. If it is "all" being used by the game, then when it wants to update, it "may" need enough room to be over double what the games size is now. This is because some games do more than just add a small amount of data during an update. Some require the entire game be altered. Meaning you would not have nearly enough space on the SD card.
A larger card, say 32gb or even a 64gb, then you would have more than enough space for your game, any updates it required and lots of other things.
The only other thing I can think of might be the problem, is if the update is just not allowing it to be done on a card. Which can give a false "not enough space" message. But I highly doubt that is the problem.