Slider Bar for action: useful or useless

[Miami_vice]

I have created a slider bar inside a game where one an select his desired level. In this case it's the time between monster spawnings. There are light indicators nearby that each of them has its own meaning.
Green light flash when a monster is spawned. You can select up to three at a time. To the left there are 2 other indicators - red and yellow. Red is activated if system is trying to spawn new actor in a place of other actor. It cannot be done because actors would stuck in each other. Instead red lamp flashes. But at the same time that particular actor is spawned in a free area. Time is not lost. Anotehr light - yellow. It indicates that there was attempt to spawn in a forbidden area - base perimeter or lava lake regions. Again without time waste it is spawned somewhere.
Process can be stopped anytime by pressing the main button to the left from slider bar. Or maybe it can be done under any certain conditions.

What do you think? Is it useful thing or abnormal improvement that can ruin any gameplay balance?

[ramon.dexter]

This looks cool. Would you share the wad, so I can look at the code? I'm interested in this.