I disagree.
Vapor in a bag has a much longer time to condense while its sitting in there, leading to an (IMO) greater loss of THC before the user has actually inhaled.
I also find that bag vapes require a larger load than whip vapes in general.
I also don't understand your math, because you didn't show your workings
Here's how I see it:
Lets say that a set amount of weed will produce the same amount of vapor (which I'm gonna call "THC Units"). and for simplicity sake, I'll assume the condensation is the same between a whip and a bag.
Whip vape:
4 hits
25 THC units per hit
12.5 THC units per exhale
50 units absorbed, 50 units exhaled
Bag Vape:
25 hits
4 THC units per hit
2 THC units per exhale
50 units absorbed, 50 units exhaled.
I was actually trying to imply that if there is more air to thc ratio, you wouldn't be exhaling as much thc as you would if you are using a higher thc to air ratio. Just like comparing a bag with more air to thc than a whip which is less air to thc.