Imho yes, you can use different concentration if the absolute dose is correct.
I think I got the one for dogs last year when one of my does, 6yo, had EC. This was the second line of treatment though, first was an antibiotic and fluids injected every day for a week, that showed results pretty quickly (sorry, can't remember which antibiotic). The panacur was just the cherry on the cake to make sure it gets as good as possible, my vet is not a fan of it but I insisted.
Anyway, the reason for the outbreak most likely were ovary cysts or a tumor, which made her hormones go haywire and made her dig and work like a maniac, which exhausted her - that's when EC got it's chance. She didn't take the last two times I triued to breed her, so something was definitly off. EC didn't come back, she lived for another 7-8 months, and she was not in the condition to consider surgery.