I don't PvP anymore. I haven't in well over a year. I refuse to play with what I consider cheaters so my UO gaming is exclusively PvM now. When I get the itch for PvP I log on the Xbox360 or PS3, at least when I encounter undesirables(cheaters) on consoles I can leave the server/room and join another.
That said, my original testing of LMC was done years ago when I did PvP. HLA defeats the purpose of a bushido dexer that spams counter attack for extra damage. I have already crunched numbers for HLD and am well inside the green zone. HCI has been calculated taking into consideration HLD also. The suit I was (am building - thanks revert) building is for a PvM dexer and I had the choice on jewelry for an extra few points of stats or 3-4%DCI. If DCI worked in 5% increments, a theory you have almost certainly discredited, then the DCI would be wasted.
One good thing about the revert is that I was able to test the suit against Bosses with the stat bonus instead of DCI and found it worked better then expected. Too much DCI defeats the purpose of counter attack. When I was running with higher DCI often my icon would highlight and stay that way until the spell naturally wore off, never having actually had the chance to trigger (I have parry). I believe I have found that "sweet spot" where the spell is triggered everytime yet not immediately upon casting(meaning I'm parrying more but not enough to nullify the spell).
Ok, so I caught myself rambling... sorry. Again, thank you Sir for the reply and the information which was most helpful.