I never noticed that !
Any date on this page relating to a soldier is in July 1800. Its part of a bigger collection - so perhaps a book updated after the event.
This page contains only Soldiers named McIntosh started with Alexander at the top and alphabetically down to two Williams but the last name is a David McIntosh! I think ages are correct as they can be for the time when discharged.
Searching more - I have seen there is another Donald Mcintosh, also a weaver, from - Devoy, Inverness (another unknown place) in records from the Chelsea Hospital. This is a slightly younger man - at 26 would he have recovered to marry and have family (in Inverness) whilst recovering from a wound to the head, received in Egypt in the Chelsea Hospital ? Leaving their care in 1802. Possible but doubtful, the dates don't fit as easily, as first child born in 1799, though the others 1804 and 06.
The joys of my Mcintosh and Frasers from Inverness - just so many of the same.