Assuming the meter is working correctly, and installed in circuit correctly then there is a problem with your antenna system (feed-line, adapters and antenna). Now begins the process of elimination. You may wish to try your measurements again using the shortest possible cable length and different adapters as you have them available to see if results change.
I am not a fan of cut-by-chart trimming of antennas. When an antenna is known to be long for its intended purpose, I prefer to trim a little and measure, then repeat as necessary so as to sneak up on the target value. Doing so helps you know where you are getting close (because SWR gets better with each snip) but also when you have gone too far (because SWR starts to rise). Be aware that at high frequencies, minute length changes can cause big changes.
It is possible that you may already snipped it too much, but also that you have not snipped it enough. Further, If you are testing using repeater input frequencies (467 MHz range) and the antenna is actually tuned for 462 MHz range, then the 467 numbers will appear higher than the 462 numbers.
Snipping of course should only be done on a basic antenna, or one that is, by design, intended for sniping and/or you have advanced knowledge antenna designs. I don’t own your specific antenna, so I cannot cannot from experience comment if it is designed for cutting or not.
For what is is worth, there no such thing as an SWR of less than 1. The first number is always 1 or greater, and the second number is always 1. Collectively they would appear as follows: 1.5:1, 1:1, 1.15:1, 4.7:1, etc. So .8:1, 0.5:1, 1.25:2 are all examples of invalid SWR values.
Hope there is a little nugget of assistance in there.
