You may be right, but I think you are placing too much reliance on a single cenus age especially as the quoted entry gives his age as 25 as read from the actual census entry NOT from the LDS transcripts.
Also Ramsey is in Maughold

1871 shows 4 listings, 16, 17, 19, 19.
One 19 is married, the other an apprenctice to James Teare, draper
The 17 year old is fishing on Vesper
The 16 year old is a labourer to Isabella Keromde at Ballaloma, birth place Maughold