Maggie 1900 on stock 99 5.3. Hard shifts off throttle

[HRD]

I just installed a Magnuson TVS1900 on an otherwise stock 5.3L 99 Silverado 2wd. It has the Magnuson base tune in it but I turned off the EGR codes since the TVS 1900 has no provisions for EGR. It runs fine, but when idling or low throttle rolling through a parking lot, it shifts real hard from 1st to 2nd. I noticed the shift time was changed across the board. Could that be the problem? On throttle shifting is fine.
Attached are the stock tune and the SC tune for comparison.

Any other suggestions are appreciated.

[Ben Charles]

Have you logged engine tq while looking at this?? Probably coming from shift pressure, could always introduce some Tq management there as well to soften it.

[HRD]

Have you logged engine tq while looking at this?? Probably coming from shift pressure, could always introduce some Tq management there as well to soften it.

No,

I'll try that tomorrow. I noticed that the changes to positive Force Motor Current were all at 48psi and above with no changes below. I also noticed that shift pressure changes were all done at 380 ft-lbs and above with no changes down low. However Shift Time was changed to 0.200 across the board at all torque levels. Could shift time be the culprit?