Brod & Taylor Baking Shell

Toast

Hello bakers,

I’m hoping to hear from people who has used the very expensive B&T baking shell to bake sourdough (or any kind of bread) as to the results they had. 
After much mulling about it, I think the price is excessive for what it is, and mainly because I’m kind of tired of lugging my 2 Romertopf bakers in and out of the oven every time I bake, I ordered the shell. Yesterday I divided the dough into thirds. The first one I baked with the shell was flattened and burnt around the edges, I gave it another try with the second portion and same results. So I baked the third one as I always do in the Romertopf and got the same consistent good results. 
Temperatures used were 475F for the first 25 minutes covered and 450F for the last 25 mins uncovered.The recipe i used is the Pain de Campagne from K Forkish. See photos below. 
I appreciate any comments. Thanks.