Okay, I think it's a liitle bit off topic. Since I like your application "FSUIPC" very much and I think it is a must have for all serious simmer, I will explain it for you very slowly and for understandability without any quotes.
When you consider MS-Applications you can see two things: "save" and "save as". I think, you are agree with me.
When you consider FSMS (also a MS application) you see only a "save as" possibility. I think, you are agree with me, too.
I don't want speculate, why MS did it in such a manner. I consider the facts only. The only way is to ask MS, why they handle MSFS other than all other applications I know from MS.
Your application use no workaround, because the saved name all times is other than before. My failure. But when I want to save my flight by hand a second time with the same name, I have to do a workaround with "save as". Therefore I wrote "real save" and I think everyone, who want understand this, can understand this at the latest after this posting.
Once more, I don't want to make your software bad. It is the thing, I searched for. Furthermore I think, there is no other way to do it. I will ask LEVEL-D, why your software don't work which such a great plane and why saving works superbe, when I do the steps by hand.
I hope, I could help you. I did my very best.
Again, thanks for the facts in your second to last posting.
Regards,
Frank