Hello user13332 (please change your name..),
I would say that the benchmark needs to take into account your growth strategy. If you are running with no investment for future growth, your costs seem very reasonable to me, but if you are comparing yourself with companies that do invest heavily in future growth then it won't be accurate.
So just be careful who you are comparing yourself to, put that in perspective of the stage of the company you are looking at.
Also remember that investment in infrastructure is often time in stairs shape. Big investment all at once (you are at over capacity), then nothing until you run out of capacity, big investment again, etc.. You will see those kind of investment made after a round of funding for example.
I know I'm not giving you a straight answer but putting a bit of context around your assessment. Hope this helps.