The problem with the number you found
Somebody in every planning meeting eventually cites an industry figure for how long deals should take. It is worth asking three questions before that figure influences anything. Who was in the sample. When does their clock start. And is it a mean or a median. In most cases the answer to all three is unknown, which makes the figure a piece of atmosphere rather than evidence.
The deeper issue is that industry is a weak predictor. Within any sector, a straightforward purchase decided by one owner and a multi-site rollout requiring three approvals will differ enormously, and the sector average describes neither.