Regular Cake Pan to Tube Pan Cook Time Conversion

I'm going to take a wild guess at what's happening, based on what I know of thermodynamics, (but I could be wrong about the whole thing)

When a cakes and bread bakes, it bakes from the outside ... as it forms a crust, it can no longer rise. (for yeast breads, this is why we slash the top, so it can get a little extra rise out of it)

With a cake, as the sides set, it'll continue to rise in the middle, creating a domed top. With a metal tube pan, the heat from the outside of the pan conducts to the middle of the pan, so the middle will set shortly after the outside.

...

With the silicone pan, you've actually got an insulator ... the heat's not going to conduct to the inside, so it's going to be able to rise longer than around the inside -- basically, the domed cake, but you've got something for it to stick to, so it doesn't fall back down as it sets.

As I don't think the issue is distribution of the batter, I'd recommend trying other techniques to reduce the domedness of the cake -- cook it at a lower temperature (try 25F / 15C lower) for a longer time. You can't remove the problem entirely, but you might be able to reduce it.

I'd also look at the instructions that might've come with the pan -- it's possible that they have reommendations on how to deal with the problem. (and it's possible that this might not be as significant a problem in convection ovens, but replacing your whole oven for a set of pans is kinda silly)

It's important to distinguish between the two different types of "crisping" that both happen in bread.

The first is the Maillard reaction which is caused by the sugars reacting with proteins; this is facilitated by high heat and low moisture, and is what actually causes the bread to turn brown (and eventually to burn).

The other is simply the evaporation of water - drying it out - which can make the bread or crust noticeably "crisper" without any browning.

The Maillard reaction happens at 154° C / 310° F, which is much higher than the boiling point of water (100° C / 212° F), so the evaporation happens first. If you put a piece of bread in the oven at a low temperature and leave it there for half an hour, it will crisp up significantly but not brown.

So essentially it depends on what kind of "crispiness" you want. High heat will cause the Maillard reaction to occur and that will crisp it up faster, but you have to shorten the cooking time, otherwise it will burn. Lower heat, on the other hand, will crisp much slower - and if the heat is too low, you won't get any browning - but you can leave it in there for much longer and the crust will keep getting drier (i.e. crispier) due to the water evaporation.

The instructions are correct. High heat causes more "crispiness" in some applications, where almost all of the crisping comes from the Maillard reaction or caramelization of some kind, but bread is an exception because of its porousness and high water content (easy for water to evaporate).