thanks for the suggestion I already have thought about it. I can see nothing wrong about it tho as I already have done it on my previous client.
I think you misunderstood my words there.
It shouldn't be like saying publicly even if you're offering such things that I'd call as a discount on 5 weeks rather than 1 week free on buying 4 - that's how I see it.
That is how I value my client giving them an extra time is not a big deal at all and it will also do not mean that the quality of my service goes down.
I never said that you will compromise your quality if you give a week or two free to your customer, you never should because that would affect their reviews about your services only. It's good if you really maintain your quality at the same or even better levels and provide best of the best services to your customers.
If the client will not like my service and will ask to remove their signature then I'll do as they say. Plus if they will demand a refund and If in my judgement that I really did not do my job properly I will give them a portion of it
I'd suggest you something over this as well.
Don't use those words like if they won't like your service, you'll do what they say. Instead, just set some terms for any such conditions if ever arise, because your client may demand for anything which you may not find suitable for your reputation or your service itself.