Ladder test, advice needed interpreting results

P7M13

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Greetings,
I don't claim to know what I'm doing when executing and interpreting a ladder test. For years, they were FM to me.
From the attached photos, I see nodes at 45.2 and 42.3 grains AA4350
Specs:
Ruger M77 Hawkeye Stainless, 7mm-08, 20" Barrel, anchored in Lead Sled with 25# of lead.
Shots at 200 Yards. 68°F, very light breeze. A flag football plastic strip was hanging from the target, I'd wait for it to stop before shooting. Temp was comfortable, but there was a good amount of mirage in my scope. However, the shift in the image was all up. I did not see angled or lateral shifts in the mirage.
Rounds:
Lehigh Controlled Chaos bullet, 05284142CuSP, 142 grains, loaded to 2.800 OAL.
AA4350 Powder, Petersen Cartridge Co. brass, CCI #200 primers
I loaded groups of three from 42.0gr to 45.2gr. in increments of 0.3 grains. Starting at about 43.7 grains, these were all compressed loads.
Confirmed the rifle was still sighted with some plinking rounds, then started at the low group and moved to high. {edit to add} Waited ~1m between shot strings to enter notes. At no point was my barrel too hot (i.e. >~140°F) to the touch. {/eta} The groups started to open way up, so after my 6th string, jumped to the top loading and planned to work my way down, 45.2 looked good, so stopped with that one.
No chrony data. Thought I'd do that next after selecting good nodes.
Thanks in advance.
 

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