Why?
3 RFCs - Kitchen, Downstairs and upstairs.
Downstairs r2 e2e = 1330 Ohms.
(1 leg of downstairs to 1 leg of kitchen = 650 Ohms And the other 480 Ohms.)
Kitchen r2 e2e =0.78 Ohms
Upstairs r2 e2e = 0.67 Ohms
I have ideas - kitchen rewire picked up something, somewhere in the refit. Old...