Okay, so, what other evidence there is that implies it is the same?
You can't use that enyclopedia entry since CTDS never refers to the place as 'a Reptite's Dimension', to even think it's implied it's the same place. The game refers it as the 'Lost Sanctum'.
The reptites aren't evidence either, since as we know there are an unknown number of dimensions, it's highly likely they may exist in many of them, so their existance alone doesn't make it a 'reptite's dimension'.
And, if the evolution to Dragonians was natural, then there can't be a Gaia's Navel like sceneraio (isolation from the rest of the world caused them to not change like the rest) for these Reptites.
As for time differneces, yes, there is a chance is not parallel, yet there are many factor that still imply a large gap of years. From turning the Saintstone to Waystone, the ladder that breaks in Mount Emerald, the fact they forgot of the Ancient Tower with the statues, etc.
Yeah, this got off-topic, but that is to be expected. You claim it is the same, so I ask how, but that first evidence you brought isn't enough since it can be denied with the above.
If only I could remember where discussion about the Lost Sanctum was, this could be solved already.