paul—
You are doing nothing wrong as such. Pharma dosage and strategy needs seem to vary hugely from person to person and with time and situation.
Some will be floored dosing 40mg, others (such as myself) only see a start to psychedelic effects with much more. I found I need ~250mg harmalas (freebase, in citrus juice) and at least 180mg DMT fumarate to get low level effects.
Keep experimenting. I need to dose high with all psychedelics I have tried so far but I'm cautious. I wanted to find the pharma dose that would get me where I aimed to go but at the same time I didn't want to plunge myself in further than I wanted to if I could avoid it (at first at least). It took me two years of occasional tests to find my dose and a vaguely effective dosing strategy. There really is no rush.
It sounds to me like you have found your harmala dose but you just need to play around more with DMT dose. Try adding 20mg each time until you try, soon enough you will find your place. For me timing between harmalas/DMT seems to make a difference and I have a small window of opportunity to get the DMT active. Some here have mentioned they find that dosing together works well for them, this may be the case for you, maybe not. I played around with timing and have found it doesn't work too well at the same time. 15 minutes is too little a time, 20–25 about right and over 30 minutes not effective.
Even though I have had several successful journeys with pharma and a lot of misfires to learn from I think I am only starting on working it out. My next tests will be trying double dosing —
1) harmalas, then harmalas and DMT after.
2) harmalas and DMT and then redosing the same after some time.
Something is learnt each time and even a dose that works one week will fail another week with the same conditions. It seems to be quite random for me but I am getting closer to having something vaguely reliable.
Another alternative if you are not feeling anything from the DMT is to vape when it is apparent nothing is happening, at least that way you will have an extended journey, just likely not as long as a full oral journey.