The Navy have the best harmony compliance rate because they take it very seriously. They are also meticulous in recording even single nights away from home towards the stats.
The Army take it seriously, too. I believe a 2* officer has to authorise individual deployments that breach harmony.
The RAF doesn't take it anywhere near as seriously. Most units I know use the "separated service" days from JPA as the harmony measure, and that only starts counting after 10 days away. This means that most routine dets and business trips do not count. And that's assuming units even "move and track" their pers in the first place. The RAF needs to take harmony more seriously because "undetected" breaches are starting to cause dissent at the front line, especially on RW and the Tornado force.
By the way, one reason for the differing harmony standards between the services is the fact that the RAF tends to work longer hours when "at home", eg providing QRA or the AT/AAR hub. Less time "in barracks" and no POETS day in light blue :-)