Parking Lot Striping Lines Fading Fast! Advice Needed for Murfreesboro Business

Hey everyone. I run a small office building near Medical Center Parkway and our parking lot striping is basically invisible at this point. We had the lot sealed about 18 months ago and the lines were restriped at the same time, but now you honestly can't tell where spaces are supposed to be. I've had two near-fender-benders between tenants because nobody knows where to park anymore.

I'm trying to figure out what went wrong. The company we used said the paint would last "3-5 years minimum" but we're not even at two years. Is this normal for Murfreesboro weather? I know we get a lot of sun and heat in summer, but this seems extreme. One of my tenants mentioned something about thermoplastic being better than regular paint, but I have no idea what that means or if it's worth the extra cost.

I'm getting quotes from a couple local places but honestly don't know what questions to ask. Should I be asking about paint thickness? Type of paint? Do I need to reseal first or can you stripe over old sealcoat? And realistically, what should I budget for about 25 parking spaces? I got one quote for $850 and another for $1,400 and I can't figure out why there's such a huge difference.

Any advice from folks who've dealt with this would be amazing. I just want lines that actually last this time.