Just reaffirming what was mentioned above by Mr. Scott... they didn't say no. They want to have a discussion. I would think you may be able to get what you are looking for.
As to why they would recommend a different tone... to prevent interference, of course. We have two repeater systems here that share 2m pairs with other networks about 100 miles away. Both have flipped in/out compared to the systems near me. Often, during the warmer months I can hear mobile operators on the fringe of those repeaters, on the output frequencies of my local systems.
I mention this because, you may have a repeater system nearby that is using the same pairs and PL tone you would like to use. Even if it seems improbable to have interference, that risk may still exist. That is why we use the coordinators. They are (typically) in the know.