The Half-Blood Prince, it Really is a single mission theoretically. And as I told you before it is still intended to be a SINGLE MISSION but dyom is very restrictive on how large the mission can be. Add to that how... odd the theme is. Making a 100 objective mission with less than 100 actors is impossible for me because I try my hardest to make the missions large scale, and make the cutscenes fluid and smooth by hiding and showing actors depending on the movement of the characters.
However, since this theme restricts the designer instead of making him more creative in making the mission (which I tried to do) then I resorted to splitting the SINGLE MISSION into two halves of the same mission. buuuuuut ya know, according to the rules downgrading the mission (by cutting some of the actors in it) is better than going just a tiny bit off limits with it.
So what I'm asking is for you to review the vague rules and look at it from another perspective: The last mission of GTA San Andreas End of the Line. Now, that is a single mission right? Well technically it is three missions but they play immediately after each other due to technical issues that come with making a mission that big.
You can look at my entry the same way, it is a single mission but just split into two parts. Firstly, because of the obvious limitation on the number of actors. And secondly, because it also serves as a checkpoint because my mission is long, and failing near the end is very frustrating so the player can just restart the mission from the second half of it.
In some ways you are right, in some not but overall this would be unfair for others. For example: you're using more than 100 actors in one mission, which means you have more possibilities than designer that can use only 100.
COTW MOTW has it's own rules and designer have to adjust his mission them. Limits f*cked up my mission too and I need to make some tweaks to make it work. ^^