TS Chip questions

I have a TS chip installed on my mostly stock 02 7.3 van (140V IDM, FRX, HPX, CAI, but all stock injectors, turbo, fuel pump, exhaust etc...) and I have a couple questions that have been nagging at my mind about it. Maybe someone can shed some light as to how this thing works.

The 6 positions are programmed as: Stock, 50hp, 75hp, 100hp, 140+ Extreme, No-Start

Now, when I'm in Stock, 50hp or 75hp, I can reach 24psi of boost (via my scangauge) when I romp on the pedal. I get a little trail of black smoke on the 75hp setting but nothing big and obnoxious.

When I'm in the 100hp and 140hp settings, I can only get to 16-18psi of boost and I get no black smoke at all.

I have no intake, turbo or exhaust leaks. New EBP sensor and cleaned tube.

Does the TS chip fool the computer's boost readings when I'm in the 100 and 140hp settings? (IE Am I actually making more than 16psi of boost but the scangauge is only showing 16 because the TS is overriding the actual reading?)

I don't really feel much difference between the 75, 100, and 140 settings... They all seem to be pretty similar (to my highly calibrated seat-of-the-pants dyno).

And why do I get black smoke in 75hp but none of the other settings? Is the TS changing the timing of the injection differently in that mode than the others?

I know I should really pay to have some better tunes flashed to the chip, but I'm not done modding yet (exhaust is next on my list). I will likely get some better tunes done after that.