Back then when I was using Stachekip's HD Beta Player Skins which was based on the Texture Improvement Pack, I noticed something weird about the Soldier and the Engineer's arms. When reloading the rocket launcher as Soldier, he just loads nothing on his launcher instead of rockets.
For the Engineer, his arms also suffered missing bones and attachments which led to broken animations such as Engineer pretending to load a magazine into his pistol instead of loading an actual magazine, the destruction PDA's antenna goes through Engineer's hand, etc. mainly because the original Engineer's arm model was updated to have the new bones while T.I.P.'s arm model wasn't.
So I decided fixing Soldier and Engie's arm models for T.I.P. would be a very great idea. This mod here fixes various problems mentioned above with Soldier's and Engineer's arms.