Hi Lynne,
you have done a very decent job with your current sheet, but what you need are self executing macros. which will get the automatic timers in your sheet. Also unlike the link you have attached, you don't really want a start and stop timer. You just want it to automatically start once you have the hold sign selected. Another function that can be included is the timer cell changing color based on your SLA. e.g if the target time for hold is less than 5 minutes, then the cell turns amber from 4:30 to say 5:50 and post 5:30 turns red. This becomes an easy visual management, to help prioritize.
Your project needs someone who can not only understand your requirement, but also preempt your needs, and I believe I am the right person. I have over 10 years of experience working with companies like Pratt and Whitney, Accenture, Volvo.. So I can be a great asset, not only for this requirement, but also future requirements.
As with any good service, there is a cost associated. So has mine. Ofcourse you can try the $20 bidders, and hopefully not waste your time, or you can chat up with me, and I will be happy to address any concerns or queries you might have.
Regards
Amin