ABC Explorer is a front-end to a bunch of other software, and uses a version of abc2midi to do its MIDI conversion. There are several versions of abc2midi in use: the converter sites may have one that suits you better. Or if you don't mind command-line interfaces you could just install abc2midi on its own, or even tweak its settings or source code to get the best fit to your needs.

You can guarantee that a package-other-people's-stuff solution like ABCExplorer will never have the most current version of any of the software it incorporates. That may or may not matter to you.