hey sense!
i kind of agree with what JBC is saying, but dont take a confidence knock. switching to flower now is a perfectly normal thing to do, some people go 12/12 from seed. so really everyone is right.
what is important is how much time you have to grow them (all manner of reasons why people want a fast grow) and the room availible to grow them.
remember that volume of nodes is far more important than height, and tall plants are NOT conducive to indoor growing because synthetic sun doesnt have any range to it.
a plant put into flower under a single light that is 6" tall but has 10 nodes will probably produce more and better bud that a 2' plant with 15 nodes (pre stretch).
sometimes its best not to look at the clock. compare how many nodes your custard creams had when you flowered them to how many this grow has. thats your benchmark
i totally agree however that they should be over their shock before flowering.
i also notice, even on the best plant, some small signs that something is not quite dialled in right. next drink i would run a little more than usual through to flush any salts and look very carefully at the nutrient breakdown of your feed to make sure your not giving too much of something and starting to cause a lock out.
are you PHing your water when you feed? ph imbalance can also cause identical symptoms to an imbalanced diet.
i would even think about lowering your nute strength a bit while they are stunned, they eat a lot less when not growing at full speed
the worst affected one either needs to be culled or add 50% extra water to its share of the feed, its now so far behind the others that it needs a weaker food than them