According to Slipperorchids.info they get between 4 to nine flowers per inflorescence, but I can't tell you how long they'll last since I've never flowered a Phrag before, let alone a pearcei.
But now to why I even bothered to write in a thread about a species I know close to zero about; I have a similar problem with my Phrag Green Hornet (it's half pearcei at least :wink: ) as you had before. I hope it's okay if I highjack your thread for a bit?
So, I've had this guy since October last year and in the beginning I watered it waaay too little, so it was not happy with me and its oldest fan never recovered after this and died eventually. It also suffered ugly leaf tips, but it doesn't get any more of those. Now, the problem is that the top of the plant is not growing, at all I think, and I've heard they are supposed to be quick growers, but mine never got the memo (the issue is obviously owner related, but let me put the blame on the plant for a bit at least)...
This is how I care for it; I water it every second or third day and change the water in the saucer at the same time. I feed it often, weakly, with K-lite and seaweed extract, but not every watering and the water I use, is "sort of" purified (it's RO for poor people, which means it's not as sterile as RO water is, but not as... "diluted" as my ordinary tap water) It's potted in bark/sphagnum/perlite, but I was thinking that maybe it's time to repot? It has been in the same substrate for about eight months now so it should be pretty decomposed by now, right? It's standing close to my T5 but not underneath it and at least the colour on the leaves look okay. It's planning to do something, but I don't know what. It could be a new leaf emerging on the mature fan, or a stem, I don't know.
Here's how it looks like now (it was so big and beautiful when I got it :sob: ):
Here's one of its new roots out on some sort of exploration trip (indicates that the top of the substrate isn't too dry at least):