Hi Loretta,
Your Creamy Yellow Giant zinnia may have been performing "as described" by the seed company. For example, Johnny's Seeds says this about their Creamy Yellow Giant zinnia:
"Similar color and habit of the Benary's Giant series but will produce 4-6" single, semidouble, and double flowers."
https://www.johnnyseeds.com/fl...
Johnny's pretty much admits that the Benary's Giants are better zinnias.
ZM