Performance within team context, especially depth at the position
1953-54 Wings RWs
Gordie Howe - 81 points
Other Wings RWs - 59 points (Prystai 27, Dineen 25, Stasiuk 7)
1955-56 Habs Cs
Beliveau - 88 points
Other Habs Cs - 84 points (Richard 40, Mosdell 30, Leclair 14)
Based on the above, it's likely that Beliveau outscored Howe despite playing less ice time in these seasons.
Beliveau may well have peaked statistically in 55-56 in part because it was the weakest season for centre depth behind him. Henri was a 19 year old rookie at a time when teenagers could rarely make the league. Mosdell was 33 and in his final full season.
Henri scored 50+ points in the next 11 seasons, and Backstrom and Goyette emerged as Montreal's #3 and #4 centres, both of whom peaked as top 10 scorers in the league when given the chance. Montreal's whole team was built around strength down centre for most of Beliveau's prime. It's not surprising that Beliveau was less dominant in the scoring race while playing 20 minutes or less per game.
And if you look at those Detroit rosters and their lack of RW depth (next to non-existent between Prystai/Leswick and F.Smith/MacGregor), it looks very likely that Howe was playing 25 or more minutes per game.