Thats what I never liked about those types of spells, they're all useless once you get past level 25 (thats the highest they can go as far as I'm aware)
I agree the lower level ones become obsolete, but if you make them at max magnitude and have 100% spell effectiveness (no armor), they will work at any level. That is what I do.
Here is a UESP quote: "The maximum possible level of these spells, even at the Spell Making altar, is 25. However, the maximum strength spell, despite claiming to only work "up to level 25," will in fact work on any level enemy — as long as your character has 100% spell effectiveness. For example, casting a level 25 Command Humanoid on an NPC of level 34 will succeed. This quirk prevents these spells from becoming effectively useless for high-level characters, who will only meet creatures and NPCs with levels higher than 25. If you are wearing any armor, even with armor skills at 100, the maximum magnitude of a spell becomes 95 and therefore will only work on enemies up to level 23."
And here is the reference link if you want a little more data: http://www.uesp.net/wiki/Oblivion:Magical_Effects#Magnitude_to_Level_Conversion