You're spot on there Lurkio! Here's their reply:
The reason is a historical one, and we have never done it before T+36. It is only now that the charts are broadcast on the web that people notice that some things are not there , like the thickness lines at T+24.
I will pass on your comments to our developers and forecasters and see if they can change it in the future.
I hope this helps.
Cheers all
mcdhu