by the rules, OER also does not apply to training packages (SM:P 172).
The cost to a skill or category indicates how many ranks you can purchase, this is unaffected by training packages.
So a training package can award ranks in a skill or category, the character can still use development points to increase that skill more. Body Development is a bad example as there are no OER modifiers to that skill.
Let's say that a Soldier character has the Natural Facility with Armor talent which allows one armor skill to be classified as Everyman, he chooses Power Armor.
Later, he takes the Force Recon training package, this assigns 3 ranks to the Armor-Heavy category and 3 ranks to the Power Armor skill. He can still purchase 3 more ranks in the category and 3 more in the skill, giving him a total of 9 ranks in each for that level. that's 3 from the package plus 3 x2 for purchasing an everyman skill
Talents & flaws and the training package are found in Future Law