Sounds about right… but what decarber machine are we talking about here?
When decarbing a big dry chunk, the inside of the hash will probably not get hot enough.
Decarbing hash dry may not work very well, unless you loosen it up into powder or mix it with a little bit of coconut oil or olive oil, or both. This way the heat will be able to penetrate throughout all the hash.
I decarb always in two batches, full batch at 100 C / 212 F for 1 hr 11 mins, take out half and let the other half go on until 2 hrs 22 mins.
Then eat a little bit of each. Gives me a more balanced effect, because it creates a wider diversity of cannabinoids; THCa, THC and CBN in more equal ratios.
Decarbing everything at once at high temps mainly creates a spike of THC, which may not always create the most comfortable feeling.