Pajama pant in brushed cotton-linen

I purchased XL PJ pants over the holidays that fit well, so assumed to buy the same size. These are wayyyyy bigger in the waist and are barely wearable. Shouldn't there be some consistency in the sizing? It's a nice garment though, so kudos for that!

These pants are stylish and comfortable. The cloth has a remarkably expensive feel to it. And their single rear pocket, which is additional to those at the front, is an unexpected bonus