Healing macro <mo> not always working

I was setting up macros yesterday and set all my single target healing/buffing skills as follows:
/macroicon "Physick"
/ac "Physick" <mo>
/ac "Physick" <tt>
/ac "Physick" <t>
/ac "Physick" <me>

So if I am moused over a target, it will heal that, otherwise my targets target, otherwise my target, otherwise me.

However if I mouse over something (for example my carbuncle), take my hand off my mouse to be 100% sure it is not moving, and spam my heal button it will sometimes heal the summon and sometimes heal me. Even though I am pressing the same button using the same skill on a non moving target with a non moving mouse, like 75% of the time it executes the <mo> line and 25% of the time it executes the <me> line. If I take out the <me> line this problem goes away however I do not want to have to hotkey twice for all my single target healing and buffing skills.

Is this a problem for anyone else or is there any way to fix it? Or could it just be a non-solvable latency issue.

Edit: After more testing it looks like it might not the <mo> line that's causing it, here are some results

/macroicon "Physick"
/ac "Physick" <mo>
/ac "Physick" <tt>
/ac "Physick" <t>
/ac "Physick" <me>

When mousing over someone, targetting someone, or targetting a monster targetting someone, it will usually heal the right person sometimes heal me instead.

/macroicon "Physick"
/ac "Physick" <mo>
/ac "Physick" <tt>
/ac "Physick" <t>

Works for mousing over someone and targetting someone, it will never heal me. But when targetting a monster that is targetting someone else it will sometimes heal me instead (the monster does not change target). So it's probably skipping the <tt> line, doing the <t> line which heals me if the target is a monster. And I can't heal myself when I need to with this macro so this isn't optimal.

/macroicon "Physick"
/ac "Physick" <mo>
/ac "Physick" <me>

Work fine when mousing over someone, will never heal me on accident unless nobody else is under my mouse. But I can't heal targets so this isn't really optimal.

/macroicon "Physick"
/ac "Physick" <mo>
/ac "Physick" <t>
/ac "Physick" <tt>
/ac "Physick" <me>

Is kind of odd, with this one <t> is above <tt>, so when I have a monster targetted it should heal me instead of the monsters target (on the <t> line, as a <t> will default heal me if the target is a monster), and it usually does, but occasionally it heals the tank (monsters target) instead, skipping the <t> line and doing the <tt> line.

It's all kind of confusing to me, it just seems like every so often it decides to skip lines but it's hard to see what's causing it with the results I'm getting. The most likely thing seems to be that the servers have trouble interpreting my macros properly because of high latency (I live pretty far away and seem to have other latency issues like with AoE detection).