Couldn't the roomier casemate of the Jagdpanther mean that the loading may be faster compared to the King Tiger and its less roomy turret? Not that I've ever clocked the loading time of the King Tiger in AH.
So far it appears that HTC has taken the better of the printed reload times for most of the tanks. The Panther is noted for being able to fire 6-10 times a minute and in AH it reloads every 6 seconds (10 shots a min). The Panzer IV and Tiger both are noted as having the same "6-10 shots per minute" reload times (Pzr IV = 6 sec and Tiger 7 sec reloads times in AH). The King Tiger reloads in 10 seconds in AH. Multiple printed sources show the King Tiger to have a "4-6" shots per minute", and HTC has given it the 10 second reload time (6 shots a minute). I've not ever been able to see the inner workings of a King Tiger or Jagdpanther so I can't comment on ease of reload. I would like to think that the designers had ease of use in mind when they designed it, but who knows.
This is one of those areas in AH that are ultimately arbitrary. HTC has to take in to consideration the experience of the crew, the training of the crew, the breech mechanism of the cannon, the length and weight of the ammo, and the location of the ready rounds. There really is no set reload rate for a tank, it is ultimately based on how fast the loader can grab a new round from the magazine, shove it in to the breech, lock the breech, then yell his "ready" command. There is video on You Tube showing a Sherman M1A1 firing at a rate of 1 rounds every 3 seconds (on average), yet in AH the M4A3 Sherman reloads at 4 seconds (and no the video was not sped up).
I wish HTC would not be so set in their ways and once in awhile mix things up. Why not allow the Panzer IV F to fire at 4 seconds? Panzer IV H at 5 seconds? T34/85 at 5.5 seconds? I understand it would change the ENY and perk costs when doing so but it don't see a major shift in the Force. Not every tank crew is going to fire at the same rate. If the game swings to far in some direction to the point that HTC cant sleep at night then change it back.
Here are the current reload times for the major tanks (longest to shortest):
King Tiger = 10 sec
T34/76 = 9 sec
Firefly = 8 sec
T34/85 = 7.5 sec
Tiger = 7 sec
Panther = 6 sec
Panzer IV F2/H = 6
M18 = 5.4 sec
M4A3/76 = 5.4 sec
Panzer IV F1 = 5
M4A3/75 = 4 sec