That's totally fine IMO; nevertheless I also suggest to commit the
changes in trunk immediately after svn-upgrade'ing, otherwise the
package is still marked as "Newer upstream release available" (and
not as "Newer upstream availaible :: work in progress") in PET [0],
and others will try to svn-upgrade it. After this commit (with only
"New upstream release." in debian/changelog / as a commit message)
noone is confused anymore by the status in PET and you can afterwards
take the time to finish the package.