Hi Jordan,
Have you considered using the SDM API to create/update users? We don't use pdm_ldap_import and have a set of powershell scripts that we use to sync with AD, check for differences, then update SDM via the rest api.
Here's a rough breakdown of how they work.
1. Pull all active SDM records via the rest api and save to PS object
2. Pull active users from ad and save to PS object
3. Use Compare-Object to see what data differs (you can set a variables to the output of compare-object and filter on different SideIndicator to see what's new in AD vs what's no longer active in SDM)
4. Loop through PS objects to create or update contacts