Quote Originally Posted by jdizzlean View Post
Does this CL bonus only apply to the duration, or if it would put your casting to where you could summon another level of SNA higher to you also get to do that?
An improved caster level does not equate to a higher effective spellcasting level. The improved CL does allow for a longer duration, but also other CL-based effects (such as the caster level check if somebody attempted to dispel your summons).