While it is hard for us to say because we don't really test this out, many here who use a programmer in conjunction with their Automatic experience no issues. However, it really depends on the programmer and your car. Feel free to give it a try!
I have a similar question... I own a highly-customized Jeep (e.g. 37" tires, 4.88 axle ratio). I set specs with a ProCal module so that the speedometer et al. don’t go haywire. Wondering if Automatic will be able to keep up with this.