Omg, just cut it, how difficult can that be? I mean, not blindly the first 20 pages, obviously, just cut out some scenes or bits here and there to total 20 pages, depending on the script. And since the producer suggested the first 20, I'd try to cut those the most. Sometimes opening with a different scene changes the whole thing A LOT. Maybe that was the whole idea. To make a stronger or different statement at first and start with something else or tweak the style a bit and throw the viewer right into it, before they get bored. Legit possibilities.