That hasn’t been the formula for HKs since January as it was changed at that time to a 10% reduction in honor per kill of a player and 10 total HKs before they’re worth no honor.
Using those numbers, the first full team wipe is 400 honor,
2nd is 360 honor
3rd is 320 honor
Highlighting in the quote below is mine and link to the blizz post.
Finally, we’re updating the calculation of diminishing returns to match patch 1.12 of original WoW. When WoW Classic first launched the Honor System, we made the decision to decrease Honor by 25% per repeated kill. With world PvP being the only option for obtaining Honor at that time, this made sense. Now, PvP has primarly moved to battlegrounds where repetitious engagements can happen with much greater frequency. Starting next week, Honor will now decrease by 10% per repeated kill in both battlegrounds and world PvP.