SPF: what are the outbound Bussines Class Mail Servers, looking specifically for *.w14b.comcast.net

I'm hosting my website and DNS elsewhere, but using Comcast Business Class for my email hosting.

I want to update my SPF record to include the range of comcast outbound email server IP numbers. Business support couldn’t help, I opened several tickets with Comcast Security / Spam group but they don’t have a list as well.

Is it true that all outgoing emails servers are listed/included in _spf.comcastbusiness.net

ie: 76.96.53.0/25, 76.96.107.0/25, 96.114.154.128/25, 69.252.207.0/25

My emails are hosted at *w14b.comcast.net

Thanks!