I think your bg would be a lot better off if you ate 12 half cakes through the week.
And of course there's nothing wrong with it! One of the nastier parts of diabetes is that we cannot predict how much high bg we can have over the years without complications. We have people who have basically been running in high teens and twenties for years when they were younger who went on to live practically complication-free for the next 40 years. We also have newly diagnosed T2's with not all that bad hba1c's who have neuropathy already.
So there is no way anyone could tell you when you are doing irreversable damage and when you can get away with it. Diabetes is just ugly like that.
On a more positive note, should you decide to go all out with your cakes, please enjoy them thoroughly! No-one can take that happy, possibly much needed moment away, so it may be well worth it.