1. A significant change at the second bar would be obvious, so if you don’t hear that significant change when the song is played normally, that likely indicates that bar 1 is not properly set. If it’s an obvious change in tempo, then I agree you need more bars to obtain the average.

2. BIAB can track tempo changes in a song.

But, If you prefer to split your song so they each have their own tempo, you can merge them together using the Song Form Medley Maker. Just list each song in the proper order and set the transition to 0 and the Song Form Medley Maker will create a SGU Chord Sheet merging the songs.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.