As far as I know, there is no limit to how many elseif's you can use in a row. If some of your elseif's aren't triggering it is because, either a previous if/elseif already triggered, or the elseif in question doesn't match the conditions you've given to it.

Example:

var %a = 3
if (%a == 1) { }
elseif (%a == 2) { }

elseif (%a == 3) { }
elseif (%a == 4) { }
elseif (%a == 5) { }


In this example, the blue lines have no match, so they are not executed; the green line matches, so it is executed; the red lines are never checked, because the green line already matched above.
Blue = NO match
Green = MATCH
Red = Ignored

Example:
var %a = 6
if (%a == 1) { }
elseif (%a == 2) { }
elseif (%a == 3) { }
elseif (%a == 4) { }
elseif (%a == 5) { }


In this example, all of the blue lines have no match, so they aren't executed.

-genius_at_work