The test says the material in the first line is 7000 parts P per 1,000,000; 5,728 parts K per 1,000,000. 

When I do the math, that yields 7000/1000000*2000=14 lbs per ton of P and  11.45lbs per ton of K....so i agree with his K # for the 5 ton application but I would require further explanation for the P number. 

My guess is that the 'three times safety factor' is related to what is considered a damagingly excessive  rate of the most limiting nutrient on the crop you intend to grow.  Further reading makes me think the safety factor is more likely based on the SAR which appears to mean Sodium Adsorption Ratio and which I believe to be a measure of the salinity of the compost. 

 http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/epw8724/$FILE/cowcalf_chapter06.pdf