4r70w Rebuild

I just had the AODE transmission rebuilt in my 96 GT. Now, the transmission shifts pretty hard from 1st to 2nd gear. The shop tells me that this is normal because the rebuild included a shift kit. They ensure me that the transmission will last longer because of this. Is this true. Is a harder shift between 1st and 2nd gear expected after a rebuld. Please advise. Thanks.