Yeah, I would expect that to be the case. As packs fail, or are taken out of commission by accidents, the pool of available packs is getting smaller every day. Is Tesla even making any packs compatible with the older Model S/X anymore? (Can you put the new 5 module refresh pack in a "legacy" S/X?)
It's a weird situation from what I can tell.
My understanding of the situation on Tesla's side is this: The S/X module production lines were doing double duty making S/X 100-type modules as well as Powerwall/Powerpack modules, and now they're fully Powerwall/Powerpack... however, they can still switch gears and make S/X 100-type modules any time they want to without any real slowdown, and have done so for batches of the new 14-module 350V packs. I'd have to guess they can also just make 16 module pack batches if needed.
As for the new packs, they're not really physically compatible, and electrically the voltage is too high for the original S/X.
We do have a project for making Model 3 modules work in a modified S/X pack enclosure, but I'm not 100% sure this is something that will ever be customer-ready.
For now, our focus is on getting our custom replacement pack ready for prime time. This way you can actually get a mostly new pack (all the parts that matter, anyway) as a replacement/upgrade if desired, even though it's non-OEM. Still quite the road ahead to make it production ready and worthy of putting in a customer vehicle long term, but we're working hard to get there. The main issue in keeping costs down on this is going to be volume. We're trying to keep this completely in-house funded, but the way everything seems to be going we're more likely going to need an investment capital injection at some point to get this pushed over the finish line. Making one is expensive. Making 100+ should put pricing closer to Tesla's refurbished pack prices... but I don't really have a couple million bucks sitting around collecting dust anywhere, sadly. (I mean, if anyone here does, though... let me know.

)