Question about el34 and / or tube filaments

I noticed on one of my EL34 power tubes, that the heater/ filament is elevated noticeably higher out of the cathode in the back power tubes than in the front. all biased to .400
The filament in the back looks like a complete letter "M", but the front filament barely pokes out and you can only see the Peaks of the filament. Seems to be the same for the other side as well.
Is this just break in? Do the filaments expand and contract? perhaps the way things happen in the manufacturing process? I know its a total newbie question, i just want to make sure im not stressing a particular tube more than the others somehow.

Totally normal differences during manufacturing. No need to worry as long as the tube works normally which it sounds like it does. Remember these tubes are hand assembled. The heater will not move or change position during the tube's life.

Tubes4ever wrote:Totally normal differences during manufacturing.  No need to worry as long as the tube works normally which it sounds like it does.  Remember these tubes are hand assembled.  The heater will not move or change position during the tube's life.

Thanks, I figured as much. Just wanted to be sure.