I had seen my '60/60' rock in the store and noted down its properties, went all over the internet and read 100+ threads on the topic to have more info apart from ideal cuts. A majority of the rocks sold revolve around TIC proportions. People look for it, people advocate it, people sell it. What about 60/60? Do most people get a chance to play around with in in real life and give it a chance to impress?
Textbook proportions are the best bet to be safe with the purchase since there are less variables to worry about the diamond proportions. Everyone wants ideal, for example, what's your ideal partner proportion?

A curvy sexy lady and a sweet personality (HCA <2)? What happens if she doesn't meet your textbook values when you first meet her online/in person? Maybe she is a little/less extra here and there (HCA 2<3) but overall feel, emotion and personality makes you decide she is worth dating. Online shopping for diamonds and online search for girls lacks the physical view and 'emotional connection'.
No one here mentioned 60/60 is fake marketing like Jadeites mentioned, my salesperson did not say is 60/60 is good, neither did she downplay the rock and try to sell me a more expensive TIC. I had a discussion with her about TIC and she told me to look with my eyes under different lightings and have the feel; exclude all the GIA report and what you know for a moment. Is it a good diamond if proportion are well matched? Perhaps. Would you enter a store, tell the sales person to prepare BIC, TIC and FIC and let you compare? Well I did. I want to compare how the 60/60 will look with TIC as the control reference. Each have its own personality (assuming cut proportion is ideal for each BIC, TIC and FIC) to bring out its best. Don't be too hard up on proportion numbers after you seen the rock's light performance, but pick the best you can for each group within budget. Just my thoughts.