5 harvests per annum which is their actual current operating...

5 harvests per annum which is their actual current operating rate, time the total facility flowering area which will be 14760 meters squared, times the yield of cannabis per square meter which is around 450 grams per square meter, times 0.85 as a discount as a contingency if the facilities do not operate at full capacity.

That equals 28 tones but the discrepancy is the discount rate for each facility is different.
By FY2020-21 the 160m^2 facility is calculated as operating at 90%, the 600m^2 is calculated as operating at 85% and the green-field 14,000m^2 is calculated at 80%
That should be close to 25 tonnes.

As for the yield of cannabis per meter, there is a paper called 'Estimating adequate licensed square footage for production' for cannabis , the paper says the average output per square foot is between 40 and 50 grams.

Just convert 42 grams per square foot to be 450 grams per square meter.

There is another way which is by (flowering area X number of plants per square meter X number of harvests X grams of cannabis per plant) but I didn't do that.