How are you taking it exactly, orally? Because some of these more lipophilic cannabinoids don't work if you just swallow it, and must be dissolved in for example olive oil. However AB-PINACA is a little more on the polar side than some of the JWHs.... maybe propylene glycol or pure alcohol, something like that would be a more suitable solvent. Ethanol can contain 10 mg/ml so it should work.
Such a carrier can make results more consistent but in my experience, even then it can be hit or miss. My experience is with other cannabinoids - I quit around the time AB-FUBINACA started making rounds.
Yes usually the oral dosage is expected to be higher, unless there is some exceptional reason why smoking it destroys much more than you lose from oral ingestion.
So dissolve (experiment with oil - which you may need to warm up a little, or propylene glycol / PEG etc, until you find something that dissolves it), then titrate your dosage carefully by always taking it under the same circumstances. More or less same amount of stomach content, etc.
Noids are discussed in CD forum nowadays.