Correction of a Blessing by Saying 'Lamdani Chukecha'

There are places in Halacha where if one forgets to mention something and has already said 'Blessed are You, Hashem', they complete with 'Lamdani Chukecha' and return to what was forgotten. However, there are places where this advice is not given. In places where this advice is not given, is the instruction not to say it and complete because it is not a mandatory mention, or because it is forbidden to do so in these cases? The practical difference is whether a person can be stringent and complete with 'Lamdani Chukecha' in these cases? A similar question regarding 'Ata Chonen', which is not completed in 'Shomea Tefillah', but since there is a way to mention 'Ata Chonantanu' in 'Shomea Tefillah', it is not entirely excluded to mention it in 'Shomea Tefillah'. So, can a person be stringent and say it in 'Shomea Tefillah' if they forgot to say it in its place?

Hello and Happy Hanukkah

The places where 'Lamdani Chukecha' is not completed are places where these words are an interruption, and of course, it is not a 'stringency' to say them, but a prohibition.

[The rule is that anything that if you continue the prayer without correcting, you will need to repeat the prayer, it is better to say 'Lamdani Chukecha' and return to mention the mention. But something that is not repeated, like 'Ata Chonantanu', 'Al HaNissim', etc., do not complete and say 'Lamdani Chukecha'. And in cases where Halacha does not say to say 'Lamdani Chukecha', it is not a 'stringency' to say so, but a 'prohibition' to say so].

Also, 'Ata Chonantanu', the reason it is not mentioned in 'Shomea Tefillah' [for those who have a cup to separate with], is because the blessing of 'Shomea Tefillah' is a 'request' and it is not appropriate to mention 'mentions' there but 'requests'. Therefore, in this too, it is certainly not a 'stringency' to say there, but a problem. 

Mishna Berura, Siman 294, S"K 6