Putting aside for the moment the merits of organic vs chemical fertilizer, I believe that Bio-Gold is an organic product.
Excerpted from an on-line retailer:
Premium Pellet Fertiliser 500gm pack.
High quality slow release pellet fertiliser.
Organic feed for your Bonsai Trees repacked into handy re-sealable bags.
Insert the pellets at 2 to 3 inch intervals around the edge of the pot, or scatter an equivalent amount on the surface. Each application of Bio Gold will last approximately 8 to 10 weeks.
As far as burning the roots, a solution many times the recommended rate will indeed cause problems. Brent Walston discusses fertilizers in general and root burn specifically in
[url=https://www.evergreengardenworks.com/fertiliz.htm]this[/url]article. He describes root burn as a sort of reverse osmosis that occurs when very high concentrations of salt accumulate in the soil medium. In bonsai culture the excess will simply be flushed away by our copious watering methods. In other words you would have to make a huge blunder for this to become an issue. Note, I am not specifically addressing winter fertilization here but fertilization in general.
I would also tend to avoid sifted compost simply because of the texture. We expend considerable effort to ensure that our mix is well aerated and very free draining. Sifted compost would seem to be at odds with those goals. I am re-thinking the use of my homemade organic cakes for this very reason.
I am not opposed to organic fertilizer but for many beginning in bonsai (especially those with a single tree in their home) by far the simplest and easiest to explain is the common water soluble chemical types. For those so inclined I think seaweed, fish emulsion or even compost tea would be a better choice than compost since it is liquid and will not impede drainage. As noted, Bio-Gold is an organic product that is in pellet form.
[url=https://www.dallasbonsai.com/store/fertilizers.html]Here[/url]is a retailer that offers numerous types of fertilizer, both organic and chemical. Opa, thanks for stopping by, it is always good to get another perspective. Sometimes we get set in our ways and tend to overlook other alternatives.
Jeffrey, if you read the material excerpted above I believe you will find the answer to your question.