You were the one that's calculating pps/second so obviously cast time does mattered there... u_u; I also stated you must include Thunder's dot potency, as once again, that matters for the pps/second calculation you did.

You do realize your argument is extremely flawed because the rotation that doesn't start with Blizzard will once again pull ahead after 20 seconds? At 20 seconds it's the second rotation that's using Fires while the first one is using Blizzard and Thunder.