Well that was a quick ponder.
But for the others considering the same thing, sit bone pain in relation to padding usually occurs due to two reasons. If you have too little padding, the sit bone will press through it against the hard shell of the saddle, which can cause pain. This can be alleviated with more surface area contact. Selle SMP saddles are shaped in such a way that you can have quite a bit of surface area contact with the saddle. Some SMP saddles don't have padding at all, just a hard carbon fiber shell. Pain because of too little padding is typically somewhat sharp and usually pretty well localized.
The other type of padding related pain is due to too much padding where the padding conforms around the sit bone but there's too much material pressing against the soft tissues. Ie. the sit bones sink too deep into the padding material. This deprives the affected tissues of blood flow and oxygen. The pain related to too much padding is also fairly well localized, but can reflect to areas around the affected area and is usually a dull aching type of pain.
But the tricky part is that the dull aching pain and the sharp pain can feel exactly the same for some people. Trying to differentiate between various types of pain and their causes can be difficult.
However in the context of Selle SMP and especially the Well, it is highly unlikely that there is too much padding on the saddle. While it is the lower end type of saddle they make, the standard Well is pretty thinly padded and the padding that's there is of a fairly loose variety, so I doubt too much padding is the issue. Other lower end SMP saddles usually a lot more padding, but even then it's pretty loose stuff so they're more likely to cause chafing rather than blood flow issues.
I used to ride the Selle SMP Dynamic and had the issues you describe BUT the pain was the dull achy type I've had with too padded saddles. I was sceptical of the Dynamic having too much padding and so I went the other way and got a Drakon, which is the more padded version of the Dynamic. The pain disappeared and on my last 100k ride the saddle was the last thing I thought about. Then again it turns out I had a pretty badly herniated disc in my neck which kept my attention during the ride but still, no saddle issues whatsoever.