Not at all.. those recommendations are very arbitrary. I would recommend though to err on the side of having more power. With low power, a typical sub may be able to fill low end on classic rock or similar genres where the sub is only needed to provide a kick drum punch (but not boom or shake) or the low octaves of the bass guitar.. but will fall flat on demanding stuff.
Thans for that. I have about 250 watts available and I want to use a 10 that says 100-375. I play my system low volume a lot and wanted to be sure the sub won't sound bad.