Thanks for the bug report.This is an edge case I don't know how to handle. We sort version numbers in changelog entries in reverse order according to apt_pkg.version_compare, which indeed considers 2:2.7.0-1+exp a newer version number than 2:2.7.0-1. I checked the Debian Policy Manual and it doesn't say anything about the suffix "+exp" deserving any special treatment (in fact it doesn't mention it at all).
jik
