Half dead RCA 2A3 tube survived

Miserable RCA 2A3 has a fault, one of 2 heater filament has no light, just it became a junk tube.
It has been activated with self bias circuit for tens years. Though I gave it up and try to look for new one as a replacement. But I remembered that I have a pair of Cunningham 2A3 in my stock box.
SRPP drive 2A3 single stereo low frequency amplifier would survive.
Void tube with loosing one of two heater was put on a 245 single amplifier as an experimental attempt, self bias resistor is 1.5 k ohm.
As a matter for surprise, one lung 2A3 tube play a part of 245 single amp power tube, probably the resistor value 1.5 k ohm is effective.
The resistor value of 2A3 is 750 ohm for self bias circuit.
Consequently, this broken 2A3 tube would be utilized on 45 amplifier as an alternative. Both of them have the same UX pin positioning and their heater voltage are the same.
The number of plate is singe on 245 old tube, as half broken 2A3 has single plate so it goes well by chance? It will live longer from now.