The judges at the time always liked Manley alot more than Trenary and Kadavy. Manley may have won the 86 World title with her free skate had she not blown both figures and the short program (she was 3rd in the free despite not skating in the final flight). And she probably would have won the 87 World title had she skated her long program including the triple lutz cleanly. She consistently and easily beat Kadavy and Trenary when all skated clean programs, even with lesser jump content in some programs. In Calgary she nearly took 2nd in the short program over Thomas despite an easier jump combo and a noticeable bobble in the camel spin.
I can see people not expecting Manley to skate as well as she did, but if she skated well she was always going to be marked higher than Trenary and Kadavy regardless how they skated, especialy on home ice. I think the short program in Calgary is a good indication how the powers that be saw the 3 relative as Manleys short was quite ordinary and clearly weaker than Kadavy and no better than Trenary probably.