NTP configuration for ESXi hosts

Hi

I'm trying to get some more information on the following knowledge base article

https://kb.vmware.com/s/article/1035833

My ESXi 6.7 U3 configuration has 4 x NTP sources. two NTP souces are internal and two are External. One of these internal NTP sources is the MS AD domain controller. With this configuration do I still need to follow the recommendations in the above knowledge base or is this only required if all NTP sources are internal?