Perfect shot, no blood.
By 'a perfect shot', I'm assuming you mean a through and through hit of both lungs as they are always the most ideal target regardless of weapon or angle. Quickest drop, best blood trails, biggest target, and biggest margin for error based on what else you can hit if you miss slightly or penetrate at a severe angle(heart, major arteries, spine, liver).No reason to aim anywhere else.
When you/he field dressed the deer, did you actually examine the internal organs to see what was hit? The lungsare actually lower and further forward than many hunters believe. If you get back more than a few inches behind the point of the forleg, you get in to the liver and stomach. If you hit the top third of the chest, you're very high in the lungs and on the verge of grabbingsome spine, or worse, 'the void' above the spine which results in a flesh wound that might not kill or leave a good blood trail.