Omg, Jun is even more adorable~
And it looks like episode 20 will be the second half of Chapter 46, obviously Chapter 47 and Chapter 48.
That could be the cut off, because at the end of the Chapter was Souma sleeping on his stool.
Meaning episode 21 is 49, 50 and 51.
Or 20 could cover up to the end of 49, which is ended in the last few pages focused on Miyoko and Megumi. So Episode 21 deals with 50, 51 mainly.
It's hard to say, because doesn't Chapter 51 begin the presentations of the preliminaries? I really need to reread someitme soon. I hope others will correct any errors I've made.
Also, what happened to the front page?