Yes the 5 to 7 is typicaly from seed to first bloom, and thats even in ideal conditions sometimes. Paph Rothchildianum is notorious for taking 7 years to get big enough leaf span to bloom, but with inbreeding and bredding faster bloomers to faster bloomers they have cut it down some. Maybe 3 or 4 years on some. It is true that phrags can be grown sitting in water, but only about an inch. They can;t be grown in water up to the bottom of the soil like CPs. They still must have air to the roots. You will kill Paphs like that. Paphs like it a tad bit dryer than phrags. I personaly like phrags better myself because some have real long petals that just go and go and go. Phrags use Ants for pollination in the wild. Well some do, and so when these long errect flower spikes shoot out the top of the fans, the flowers send down its petals to the ground to give ants a beeline to the flower for polination. You can accualy sit the pot up high and as long as nothing impeeds the petal growth you can have SUPER long petals on some species. There is even a pouchless phrag. It looks so strange!
Alot of people generaly do not use the same orchid mix for their slippers. It drys out too much. Alot of people use a modified seedling mix. Heck I use a modified seedling mix for my seedlings. LOL Anywho. since these guys are terestrials you need a finer mine. Normal orchid bark is too big. I generaly take a seedling mix and add some course milled LFS to it for extra moisture retention. Most slippers resent drying out so the LFS helps hold mosture. I water freguently, and they don;t like alot of fertalizer and can be burned easy.
Oh I have to add the part about drying out is during times of the month that they are growing and its not cold. Paphs atleast can take temps down into the 40's according to a fellow at Ratcliff orchids in Fla, A large paph grower out of the UK with a satalite nursery in Fla till the end of the year, He told me if the plants are kept dry they can take temps into the 40's. He said a dry plant is not a cold plant. A wet plant is a cold plant.
I;m really no slipper expert so take what I tell you with a grain of salt.