[Mass Combat] When do the rules break?

[Tyneras]

My group has used Mass Combat for a number of battles so far, and we have enjoyed the system quite a bit.

Last night, when we got into our random brainstorming mode, the idea came up of how small a battle we could do with Mass Combat and not have the rules break down on us. Until now, we haven't had any fight with less than 50 units on each side, often 100+. Would the system still work if we, say, made a single infantry unit do a dungeon crawl, and fought various monsters in individual battles? 1 Heavy Infantry vs 1 Troll, or Dragon, or whatever. Do the rules work, or does it fall apart/give odd results? The idea came up mostly as a way of skipping character creation for quick games. The various quality and optional features make the units quickly adjustable, without requiring the time of actually building a 10 man party one character sheet at a time.