It depends on the ester. I know that EOD enanthate makes my testosterone very constant, whereas daily propionate can make my testosterone vary by up to +/-50% about the mean.
The absorption rate relative to dose is an interesting subject. I believe that at least in earlier stages it is modeled well by assuming an absorption rate proportional to surface area of the injected depot. This implies that relative, but not absolute absorption rates are greater for smaller doses. This leads to shorter apparent half-lives for smaller doses. A couple research papers have made mention of such observations, meaning that there is some experimental evidence in favor of the idea.