Choral Public Domain Library

I found a midi file on free-scores.com:
"Adams, Stephen, The Holy City"
With CPDL license

I am getting paid to do for someone a sound recording of this song,
and he plans on selling it as part of a cd.
I understood from your license agreement terms that i can use the midi file
and edit it to make my own recording and sell it.
what I did not understand is section 2 of the
"TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION PERFORMANCE AND MODIFICATION"
what is my responsibility, if any, as I am just selling my work to one persons?
and what is his responsibility for selling it in a cd?

Thanks for your inquiry. We are checking into this and will drop you a note shortly with CPDL's reply. What sort of timeframe are you on in terms of needing to hear back?

I would like to get a answer in the following week if possible,
Thank you very much.

P.S.
I would also like to know if I can write my work as an arranger in ASCAP (or similar institutes).

Any news yet?
Thank you..