SIGH<
You kids … !
There is a reason why the BBC use PPMs even to this day, y’know! They wouldn’t shell out £75-plus per meter (much more for twin-needle units) if they could sensibly replace them with nice cheap LED stacks.
All (?) LED-stack meters share the same problem, which is an instantaneous fall time. Some instantaneous peaks, such as a particularly loud snare drum hit, can appear (and importantly, disappear) on the LED faster than you can see them.
This is fine in a live/PA situation because peaks don’t really ‘break’ anything and in any case you’re more concerned with sustained average levels. In broadcasting, peaks are the single most important thing to notice and manage. You may well be sending the signal down quite a long complex chain to the transmitter or control centre, and some equipment along the line may well be set to self-protect by cutting out on severe peaks, causing a brief (sometimes not so brief) dropout in signal.
So in broadcasting, missed peaks can be a disaster, and the BBC developed the PPM and its driver circuitry specifically to solve that problem. The time constant which applies a graceful slow fall time to a PPM needle means you never miss seeing any of those peaks, because the needle can’t instantaneously ‘switch off’’ like an LED stack does.
A PPM (a proper SUM one which shows the ‘total’ level of both stereo channels) means you never again have to try to add the left/right levels in your head; and also makes it Dead Simple to train new presenters. Peak speech at PPM 6 maximum, PPM 5 average; and peak music at PPM 5, PPM 4 average. That was how the BBC trained me to do it, anyhow. ;D None of that vague ‘well, keep speech into the yellow bits most of the time, and the music a few LED bars below that, mostly …’ that you get with LED stacks.
All that said, you will inevitably be using some kind of audio processor (Orban box or whatever) on your output, so some of this appears a bit arcane, quaint, and seemingly irrelevant nowadays; but it’s still best to TRY to ‘do it right’ in the studio, and you know, even after it’s been mangled by the audio processor, a genuinely well-mixed show still sounds better than one where the presenter is of the ‘turn everthing UP’ variety. 
PS: Since your PPMs are surplus to requirements, I’d be happy to send you the money to courier them to me here in Edinburgh; purely to save them cluttering up your storage space, you understand … 
BFN
CAD