Should I Charge the Same Rate for a Repeat Project?

Make a list of all the changes required for this new project and charge accordingly. You might also want to propose ongoing maintenance services for both projects. That could create a nice recurring revenue stream for you.

It's best to charge based on the actual work you'll be doing. Since this project mainly involves reusing a lot of what you've already built, charging the same price might seem tempting for a quick gain, but it could hurt your relationship with the client in the long run. Building trust can lead to more work later on, so consider lowering your price for this one.

I believe in billing for the time I spend. If it’s going to take less time to adapt this new project, then the price should reflect that. Don't forget, you can keep working with clients multiple times, but if you overcharge for one project, they might think twice about coming back!

If it's 90% the same as the previous project, you'll need to justify why you want to charge the same amount. If you can't provide a solid reason, a time-based billing for the changes might be fairer in the long run, especially since you'll be managing two codebases.

Honestly, $2700 sounds a bit low for what you described initially. Whatever you decide, make sure to have a detailed agreement in place covering all aspects of the work, milestones, deliverables, and payment schedules. This helps in clarifying expectations and responsibilities across both projects.