Jean,
Thanks for this I had not seen it before. The fact that in the letter he states 32 years of service throws my current theories off somewhat so you could be correct in thinking it was his father. The SB Moffatt I am following, married Elizabeth Lace and is quoted as a school master on the wedding certificate but the wedding is in 1848 and I think she would have been about 28 and he possibly about 30. So from your details if in 1844 he had 32 years of service then he would have started in 1812 so he could be my SB's father I suppose. No idea how to prove that though.