Since app version 1.6.1, we support incremental mode to speedup the analysis of your pull requests. You just have to enable "incremental mode" by configuring for which branches it should be used in the Bamboo task as follows:
We also recommend that you enable creating plan branches for pull requests, because only with this mode a full analysis will be prevented when you push a new branch to Bitbucket Server and instead be deferred until the pull request is created: