After receiving some conflicting information about the new system, I called yesterday and talked to Cindy G. at the Inyo permit office. She was very informative...apparently she's the liaison for the new rec.gov software dev team, and is also the person who has supplied Steve C with the extremely useful "Unused Whitney Permits" data for 2017 and prior years.
She told me the intent behind the changes is to enable people to make full use of the permits without having to drive to LP, stand in line, and endure mini-lotteries for no-show permits without guarantee of success (as can happen on popular weekend days)
The no-show deadlines are still at fixed times for day-use and overnight (noon on the previous day and 10am on the entry day, respectively). The unclaimed permits go back into the system at random times after the cutoff (to prevent scalping and coordinated transfers). Moreover, each no-show group is a separate transaction with its own randomized release time, so there is no coordinated mass "dump" like the 2pm release for day-use under the old system.
Group-size reductions happen on a rolling basis as reserved permits are picked up, so these also appear individually at random times throughout the day, as do cancellations initiated by permit-holders.
Next-day permits must be purchased and either claimed in person by 5pm or designated for after-hours pickup by phone (4:30pm deadline, per InyoNF website
On Monday I monitored the next-day day-use permits (ie, for Tuesday June 18th). There were 7 available in the morning. After the noon deadline, that number rose to 9, then 10, then 12 at 4pm, so no-shows are apparently being added to the system.
However, those 12 remained bookable until well after midnight. I don't see how that's useful, since if you bought a day permit after 5pm you'd have to wait until 8AM the morning of your ascent to pick it up. As we know, 9-10 AM is awfully late to be starting a Whitney dayhike.
At least after 8 AM, the current day shows only as "W" (walk-up) for both permit types, implying that you have to go in person. Yet the new rules (and the VC staffer I talked to) clearly state that no walk-ups will be issued for Whitney. So it's unclear how you'd ever claim a same-day overnight permit released after the 10am no-show deadline.
Putting it all together, you have a non-zero chance of scoring a newly released next-day permit at any time after the VC opens at 8am, thanks to late cancellations and group-size reductions. Your chances then increase after the no-show cutoff. By 5pm closing, you need to be at the VC or have arranged for night-box pickup before the phone line closes at 4:30.
ISTM that the site may need some tweaking to lock out unworkable last-minute scenarios that have people buying permits they can't use. Cindy G. said the new software has had some technical problems as well (like freezing up) and also that they lack certain essential tools they once had that let them identify "in limbo" permits & manually free them up for latecomers. Devs are currently at work on resolving these limitations.