"The music is intentionally at odds with the show."
Although it depends on whose intention--that was one of the issues Schwartz had with Fosse (but seems to have gotten over)--he seemed to see it as much more earnest.
I admit, I love the original cast album--and kinda dig the 70s groove, but a lot of the cast album didn't reflect the original staging, and may have been done that way to appease Schwartz, but also because it was recorded on Motown, and was one of the first cast albums to record the orchestra first, the way a pop album would be done (also its use of pop song fade outs, etc).