This used to be popular. Perhaps in some circles still is. I believe Rex Feral
here said he did Anadrol for 3 years straight like this with no problems. I have heard some pros do orals only on training days, this is thought to reduce toxicity.
As far as stable blood levels, well yeah, but you have the injectable base going on round the clock. The oral, say taken all at once, once per day, causes a high spike and sets in motion the growth machinery so to speak, the higher the peak the higher the response. The anabolic effect extends somewhat beyond the plasma high.
Here Rex explains the idea, can apply to injectables as well as orals