Tesla used to internally have a rating system for the refurbished packs, and on remanned ones the 2 characters before the end letter in the refurb part numbers used to be related to the quality of the refurbished pack. Now they seem to hide that as far as the part number goes, but still seem to price them based on the actual quality of the refurb pack (available or targeted), with the cheapest being the worst available ones based on my limited dataset... and based on what I've seen these low end packs are pretty trashy.
I recently upgraded a 2013 60 (real 60, not software locked) to an 85 for a customer, and their core pack was a Tesla refurb they purchased for ~$10k after taxes after suffering a failure. They originally quoted $14k, but after the customer went back and forth with them a bit, they somehow managed to "find" him this lower price on the replacement... which was invoiced exactly the same as the original estimate. Gets it back, and 100% charge on the refurb pack is 159 miles (~45 kWh). (184 on their original core pack before it had errors, which Tesla kept, and about ~202 is new.) After complaining to them about this, they basically said too bad so sad, and that they don't guarantee any particular capacity or capacity match on customer-pay refurb packs whatsoever, but under warranty they have to match them to within a certain margin. How sketchy is that? You pay them for a replacement pack, and you get the bottom of the barrel, but if it fails under warranty you get something better... maybe even new. Oh, and this pack won't even hit 20kW with dual chargers, and peaks at like 30kW at a supercharger for like 10 seconds before dropping to < 20kW. Heck of a screw job, IMO.
Anyway...
Tesla's refurbs are pretty weird too, with almost every single 70/75 refurb originally starting out life as an 85 or 90, respectively, but with them downgrading them from 16 to 14 modules by removing up to two bad modules (since, as I keep trying to educate people on, you can't replace bad modules). 85 or 90 refurbs tend to be 85 or 90 packs with BMS hardware issues of some kind that could actually be repaired, usually by replacing that hardware or by fixing things like cell sense leads using specialized equipment.