Being I work in the field, I did some price checking. Four inch PVC runs around $2/foot, 4" EMT - $5/foot and 4" GRC - $8/foot. Keep in mind the fact that we are talking about fire alarm devices which can't even
handle a 4" conduit being run to it, short of the FACP and even then I doubt it. So, the largest conduit that
should be run to a device is 1" which clocks in at $.70/foot. Just for the sake of
argument discussion, lets say that you used 12/3 MC cable. That runs $.70/foot, too. As for the wire itself, even assuming worse case, that will set you back to the tune of $.65/foot.
The only way you could have conduit cost $27/foot is if you used the 4" GRC and had ($27 - $8 = $19/.65 = 29.23) 30 runs of 12/2.
Except that 30 runs wont fit. Never mind the fact that devices are daisy chained so your runs back to the FACP would be fairly minimal, especially in
your room. Hell, even the riser diagram I worked on for a nursing home with somewhere in the vicinity of 280 rooms only had
32 runs for the entire building (make sure you look at the linked image).