I work on PON and XGPON. Officially we work on a -25dB maximum, but I've seen circuits stable at around 30dB.
It's surprising how many bad splices you can ignore before it gets problematic.
-18.5dB is going to limit you to either a really good fibre path, or a really short one. Unless you have options with long-range SFPs? The constant progress keeps my job interesting at least.
This is for PON technology. 1 fibre can be split 32-ways to feed, you guessed it, 32 customers. 50g over a fibre that is split 32-ways with a minimum of 15db loss is impressive.
I guarantee those 100gbps circuits are a single fibre all the way from the provider to the customer. And they are expensive, very expensive.
Meh, I use 'as discussed' when I want to commit something I have discussed over the phone, to email. So there is a paper trail when the thing that was discussed doesn't happen, or gets fucked up somehow.
Reason 2378 to never buy a Stellantis vehicle