Even before Ves spent his Design Points on upgrading his Sub-Skills, he had already managed to raise most of them on his own. Just like any other engineer, a mech designer never stopped learning. There was a huge body of existing knowledge and the mech industry constantly came up with new developments.
If Ves didn't want to stagnate, then it was essential for him to keep up with the evolution of the industry. He did not have to waste his precious DP on quickly absorbing easily accessible articles and textbooks.
One of the only instances where Ves felt it was worth it to spend his DP to acquire instant know-how was when he needed to master Skills and Sub-Skills that were not as accessible.
To him, that translated knowledge, insights and masteries that either took a disproportionate amount of time for him to learn or were not accessible through public sources.