Huuummmm. No
In fact we are talking there about "weapon perks". Long Range perk make (PE-2)*16 instead of *8 in ToHit formula, and Scoped give *20 for ennemy at more than 5 hex (no bonus at all for ennemies closer).
Accurate perk (shotguns and miniguns have this one) add 20% at your ToHit. Some weapons have perks which don't affect ToHit, some have no perks at all.