Need help wit set analyses

[#1]

I want to summarize some fields when 2 conditions are right. Wrote

sum({<station={110,111,112,113}>}{<rtype={12}>}weight)

but it summarizes both station in(110,111,112,113) and rtype=12 separately

Whats wrong in my formula?

[#2]

it's OK just

sum({<station={110,111,112,113},<rtype={12}>}weight)