From the “Intensity Guidelines for Triathlon” resource document:
A mathematician will notice that the CV formula result is influenced both by the time and the delta between the two tests. Even if your total combined 400+200 time goes down from test A to test B, if the difference between the 400 and 200 times are greater in test B, your CV might actually increase. In this way, the CV test “punishes” the athlete for poor pacing.
Some swimmers therefore may have a difficult time with the CV test. An alternative test is the 1,000 yard time trial. Swim 1000 yards (or meters) as fast as you can. Your average pace per 100 is your lactate threshold swim pace.
so in my case I swam a 5:57 1:29/100 and a 2:52 1:26 per 100. that calculated out to a 1:33 LT, But if I would have swam a 3:00 200 1:30 per 100 my LT would have improved to 1:29 per 100. So is it punishing me for not going hard enough in the 400 should my swim in the 200 be slower than the pace of my 400. because I feel that my 200 only being a few seconds faster than my 400 is good pacing.