The change is only for the reward for top-level posts, not comments. The reward after 4 top-level posts will be decreased, but the reward for comments are unaffected by the volume of posts (or comments).
See https://steemit.com/steem/@steemitblog/steem-version-0-12-0-released
"Comments are not affected by the posting reward rate limiting algorithm."
RE: Hardfork scheduled for July 26th affects payout on commenting and makes 2 payout windows