Whether JPS get par value in an admin action depends on how that action is performed.
According to Kthomp, JPS only get par if the SPS are written off for free. However, according to Calabria, this is supposed to be "illegal" from the government's point of view.
The probability of an SPS cancellation/write-off is 25% according to Kthomp and only 5% according to Man_with_No_Name.
In contrast, the probability of a SPS-to-common cramdown is 75% according to KThomp and even 95% according to MWNN.
In case of a common cramdown - the Biden-Admin could also favorite this! - there would be a 55% haircut on the JPS according to KThomp. By 2026, this haircut on the JPS would drop to 30 - 35%.
Conclusion: Only if a release under Biden is accompanied by a cancellation of the SPS, the JPS will receive par value.
---------------------
By the way, this shows that the insinuation that JPS holders would like to see a common cramdown and prefer it to an SPS cancellation is pure nonsense. In a common cramdown szenario the JPS would receive only half as much as in the case of an SPS cancellation (if done now), so it can't be in their best interest.