Curiosity about hcg and implantation

[Cppeace]

Just curious does anyone know the avg hcg that one starts producing day of implantation? I know it is supposed to double every 48 hours. If I finished implanting say 10dpo and had 5 hcg that day I would have 10 hcg on 12 dpo and then should have 20 and 14dpo.. So I should test positive tomorrow at 15dpo then having 20+ hcg for a fr to pick up on, but if I only start out with 2 hcg at implantation then it would become 4 on 12dpo and then only 8 at 14dpo so could still test negative on a fr at 15dpo... Just curious more than anything else if there is an avg hcg that is released at implantation? If any one knows?