I thought I posted this here before and you may already know this but if it helps anybody it bears repeating.
It is unfortunately fairly easy to get these caps out of index, and the 200T is probably the worst on the oil tank. If the cap is not seated all the way in and you turn it the cap gets opened up like this cap:
If you can see the gap showing it is out of index. Just hold the top and turn the other half so it looks like this:
Now it is ready to try again. It is worse on oil tanks since they may be full to the top and when you push the cap in it gets pushed back out by the oil and is only partially in the tank, and then you twist and get it out of index. There are some reference marks but they are hard to see to line up.
If you keep trying to twist the cap and it is out of index you will force it past the three little built in tabs and now it is ruined and will need replaced.
I was working on an old 009 I got for the collection the other day, and when I put bar oil in it and sat it up on the bench, a little later I had bar oil all over the place. The screw in cap had a hole in it from being tightened with a scrench repeatedly. So it needed replaced as well.
I am OK with flippy caps since I have trained my self to be sure they are not out of index and are seated correctly before I turn them.
I suspect it is all about marketing and having something unique to talk about and spin for advertising, and all the models are using this cap to keep manufacturing costs down, so it is just one of those little peculiarities of the brand that we either love or hate.
Eddie