Actually, look at data\campaign\space_marines\default_profile\squads.lua. You can see that most squads default to level 1 with no assinged points, like Tarkus here:
But Thule starts with 8,700 XP and, what, 13 points already put in towards a melee-oriented build.
ranged = 0,
stamina = 0,
strength = 0,
will = 0,
blueprint = "sbps\\campaign\\playable\\race_marine\\troops\\sm_tactical_marine_tarkus",
experience = 0,
So you could set those to 0 and/or make him start at level 1. As for the available points, I think the game compares previously allocated points with what you "should" have (the tuning_info.rbf leveling part). What's left over is for you to assign. So if you left those skills like that and dropped Thule to level 1, I assume he wouldn't get any new points for a while.
ranged = 3,
stamina = 3,
strength = 5,
will = 2,
blueprint = "sbps\\campaign\\playable\\race_marine\\vehicles\\sm_dreadnought_davian",
experience = 8700,