I talk about that too on the blog.
The MSRP is $20 ($12 is the steep Amazon discount, not what you'll find at the FLGS). Looking at Pathfinder $35 MSRP (was $23 on Amazon), and the deduct some contents (it contains a higher page count, standees and the dry/wet erase flip mat). The flip mat itself is at least $10 of that MSRP price point. Put in slightly fewer standee tokens, and you can hit the $25 MSRP with slightly better contents.
Sure, of course you can sell different packages at different prices. They decided that $20 was the price point they wanted, not $25, and which they believe will shift more product.
Hey, maybe your analysis is right and theirs is wrong. I imagine plenty of market research went into that price point though.