Wow. Don't do these when you're short on sleep.
I decided to take another look at this puzzle and noticed that this is the EXACT SAME PUZZLE I asked about earlier. Then, I notice that I missed a key square. It was one of the same squares I missed before. I need more sleep when doing these.
Clue 8 is the key. Look at the right side. 105 dB and 1997 have something in common, neither can be 120dB. Thus, nothing on the left side can be 120dB. Securalert cannot be 120dB and $145 cannot be 120dB.
This is marked with the purple squares in my attachment below. Once that is done, there is another advanced technique that involves the yellow squares. But for that, you'll need to go to my earlier thread and see the Admin's response HERE.