Well, the source said the following: The lady looked impressive all over, far more realistic than other games even attempted. Complete realism wasn't possible, of course, and Gard intended Lara to have somewhat exaggerated dimensions from the start. While making test adjustments to her girlish figure, a slip of his mouse turned an intended 50% increase to her breast size into a 150% gain. It met with instant approval from the team before he could correct it.
https://www.ign.com/articles/2008/03/01/ign-presents-the-his...