You can combine boost.
Here is what I got, in the past week or so.
Buy any leg of lamb, so long as $18 or more, so someone linked to my card, bought it, $33.21, I got 550 points, and also got 330 or so points, for buying meat.
All up, about 880 something points.
If you got the points offer for cheese, ie, a specific one, and then buy the cheese, if you get say 250 WWR/EDR points for buying feta and get the 10 WWR/EDR points per $1 spent (say total $10), on cheese, you should get 350 points all up.
I might have gotten the cheese offer, can't remember, getting to be an old pooch now.
I didn't activate the cheese one, if I got it.
Person who has car in my household, said to just activate everything, don't buy never mind, just activate.