Two jobs exactly the same, one of them perfect, one of them... well.
Neither of these are jobs we have seen, or worked on, but it just shows the difference in how a job can be done. And when you're talking a serious commercial installation, you shouldn't have any discrepancies.
Case in point, we've had to stop installers in the past half way through a job, and pay extra just to rectify their work. They have all the qualifications and credentials, but that doesn't mean to say they actually care, or even known what they're doing.
Photo A is how it should be and photo B is how it shouldn't.
Oils ain't oils and solar ain't solar .