No such thing as DVCPro 1080I60 at 23.976 fps... DVCPro HD is a codec. One of the acceptable frame sizes is 1280 X 1080. If it's 1080 can't be anything else. The frame rates for the codec are a little more complicated. Here's a clip from the specs from Final Cut concerning DVCPro format:
- 1080 lines: Interlaced or progressive (via advanced pull-down)
- 720 lines: Progressive only
I'd take some raw footage from your editor and look at it's properties. I'd guess that it's 60i with 3:2 pulldown which must be removed to turn it into 23.976 (23.97) progressive. I don't think your editor completely understands the format.
If it were my project I'd work in a 23.976 fps full hd comp and render to something like Pro Rez 422 and use that in the edit. You'd then edit in 24P and I wouldn't render to a DVCPro codec for delivery unless that was absolutely required by the client. DVCPro HD is an acquisition codec, not a delivery codec.