Sloppy thinking. Sloppy measurements.

If you have almost 1000 reqs/sec initially, that's 1ms per request. By bringing this down by the amazing 400% (!!) percent you've shaved off 3/4th of a milisecond per request. Congratulations - you have no idea what you've been measuring. Just the way in which the request is logged can make a 5ms difference. Insignificant and completely uninteresting.

Back when 3d game programming was cool, people would get a rotating cube and show off their 1200 fps frame rate. Of course they would get upset that by adding a texture to the cube the framerate dropped by 400 frames to 800 fps. "Textures are slow!", they'd say. Yeah, right...