You're not seeing what I'm trying to show you.
The AUX tank is 30 gallons, AFT 77. Burning the first 30 gallons from the AFT tank rather than from the AUX tank dry is not a favorable trade off.
The Aux tank is furthest back of all tanks, it's a boost container used as fuel tank as you know. AFT is ahead of AUX, FWD ahead of AFT, and drop tanks are ahead of FWD and wing tanks (in the 152). Wing tanks and drop tank are pretty much on the same spot, length-wise.
Having weight furthest ahead is the best CoG you can have for maneuverability, for the same reason you have door handles furthest from the axis of rotation, also for the same reason that if you'd rather the door of your fridge open easily as opposed to heavily (as well as banging against whatever's behind it if you forget to stop it) you'll have all the stuff in it pushed closest to the axis of rotation.
This is seen everywhere, "mass centralization" as a way to make things more efficient when you want to maximize rotation or minimize energy/effort required for this rotation. e.g. Racing motorcycles attempt to compact everything near the roll axis so that the rider gains time, tires work less, etc. Same deal with 190s: that's partly why they roll so well, it's thanks to mass being near the axis.
Analogous to this is the pitch axis - it's more efficient if you've got mass distributed as much towards the axis as possible, and on a plane that's near the prop, towards the front, away from the elevators which'll effect the rotation the same way you effect rotation on a door.
So, AUX being furthest back is what you want to get rid of first, if what you're after is agility. I suppose if you wanted a plane's nose to remain as solid as possible (at the cost of agility), you'd do the inverse. E.G. if you were shooting at precise (and immobile for the sake of your E) targets such as a bomber's cockpit or a vehicle's driver.
Another analogous model is hunting arrows. You don't put weight back near the directing tail feathers for a good reason, that's the one I'm trying to illustrate..
I lost a schematic of this I had made a while back, it shows all tanks' positions on the 109/190s length.
So the reason a DT helps pitch agility is the same reason that makes AUX the best tank to burn first.