Most disapppointing to see such a load of (dangerous) untruths / personal preferences / ideas posted here.
The calculated V1 is not necessarily the "Stop V1". it might be the "Go V1", or anywhere in between.... Anyone who chooses to "Go" even 1K below a "Go V1" is asking for trouble
You are as likely to go off the end/side at
very high speed / power as someone is to go off the end at
low speed who RTOs 1K late from a "Stop V1"
Aircraft Performance is not an exact science, but based on years of experience, deaths and wrecked aeroplances. Aviation Authorities and Manufacturers have spent many hours deciding the best policy for calculating V1. If they meant it to be called 5K lower, then they would calculate it 5K lower.
Call V1 at V1. You are not storing up a decision to be actioned then - so the time factor is not really relevant. If you have not called "Stop"
prior the call (or you seeing) V1, then there is no decision to be made...
IMHO
