प्राकृत से अंग्रेज़ी में अनुवाद करने पर मूल अर्थ आता है, 'may all the evil that has been done be fruitless.' while, according to the Hindi translation pratikaman book, it is 'आत्मा को पापकर्म से अलग करना'
Micchami Dukkadam does not mean (at least literally), 'I seek your forgiveness & I forgive you.' which is what a lot of people think it means when they say it on Samvatsari or otherwise.
Hence, IMO it makes sense to say Micchami Dukkadam after १८ पाप स्थान, अविनय अशातना etc., even in case of seeking मुक्ति from previous karma bandhan of hurting someone, but not in place of seeking forgiveness & forgiving itself.
Reference : Wikipedia for the literal meaning
What made me think about it?
Messages of 'Micchami Dukkadam' in place of khamatkhamna.
Edit 1 : I should ask Maharajsa/Dadi the meaning of मिछ्छामि दुक्कड़म tomorrow & update this post.
Edit 2 : this is still under research, your thoughts & opinions on the matter are welcome. Please contribute the same in the comments below, & I will update the post with the relevant thoughts & ideas.