Hes got Ludendorf ( Mobile Practical) as Army minister - see his post on June 20th.
You're unlikely to be running a perfect mirror of his game - there's not enough information to do a perfect mirror and you're unlikely to get the exactly same trade deals or events, which then affect being able to squeeze out an extra unit here or there with a boost to practical. Id presume he delivered a few more CAV brigades than you did, or did so somewhat earlier than you. Or you didn't have Ludendorf so your Mobile practical decayed faster than his. He's also said hes going to be constantly researching the IC efficiency and capacity techs so if you've dropped back on those then that would also explain it.
One point Id note is that I'm not sure I agree with the rushing on the research efficiency techs on the Industry tab. They offer a few extra percent off the research time in days - so spending 400+ LP Days to save 2-8 days on other techs. Id rather push that LP into Officers whilst I still have Two or Three Year draft, then come back to those techs in late 38/early 39 when I'm running Volunteer Army and have already built up a huge officer pool. Minor quibble though.