Actually, I'd guess it would be the other way around, toffee being dominant or an intermediate form. It's possible the mutation in "normal" albinos results in complete loss of function of a gene in the melanin pathway, whereas toffee bps maintain some or reduced function. In which case a toffino would have a single copy of complete loss of function, and a single copy with some function. Leading to an intermediate or dominant phenotype.
Regardless, its very cool to see!