Roofing estimate for TechShield Radient Barrier - Fair?

South Texas, hot and humid… Replacing entire roof, new ridge vent, existing soffit vents, asked for quote on TechShield Radient Barrier, not the spray stuff but the foiled decking. Quote for 1800 sf 1 story 1977 typical ranch style house was almost $4k. It’s a highly reputable co I found on Angie’s List and I’ve researched enough to be comfy with the listed materials and their contract. I know that the quote they gave me for the other work they’re doing (roof itself and some hardi boards) is fair, I just can’t find much on whether the cost for the Techshield portion is fair. I found the price for the material, minimal. I found 2 mentions of what I think is a radient barrier during reroofing costing others $1300 $1400, so I’m thinking this $4k is too high but before I tell the guy I’ll pay just hall his quote on that, I wanted to check it out.

High?
Fair?
Ripoff at any cost?

(Feel free to move this to opinions)

Since the OP is looking for opinions, let’s move this to IMHO.

Colibri
General Questions Moderator