My fully evolved FMT (ch 15) produces 35,000+ per hour of coins. It also produces KP (3), moonstone (8k+), and supplies (79K+)every 24 hours. My residences at lvl 33 produce 13k+ per hour. So, as it stands now, my FMT is very, very good to me. Upgrading it only increases the coin production 4k, the supplies about 9k, and the moonstone 500 per day. I say "only" but of course, moonstone, in particular, is nice to have since I am not boosted in it.
Should you upgrade? Usually I find, in the long run if you upgrade it does because it's not just the S1 you would be getting, but the other stuff as well. If I take out my FMT I have to have 3 residences to make up for the loss of coins alone. Ditto for the workshops. And since I'd have to trade for the moonstone, that too, is a real benefit.
My suggestion is that you think more "big picture" and measure the total production you'd lose if you got rid of it. I suspect that, overall, it's a lot more than the lvl 27 mfr can do.
AJ