If I make payment according to the payment arrangement plan.

[Jit833]

1) If I make payment according to the payment arrangement plan then I will be given ten percent off.
2) If you keep your promise and make payment according the the payment arrangement plan then you will be eligible for ten percent off.


Can I construct the above sentences in such a way? Please advice.

[Grumpy]

1) If I make payment according to the payment arrangement plan then I will be given ten percent off.
2) If you keep your promise and make payment according the the payment arrangement plan then you will be eligible for ten percent off.


Can I construct the above sentences in such a way? Please advise.

Broadly, yes. In British English, per cent is often written as two words. Also, I would say, "make payments", or simply "pay", rather than your "make payment". You also need a comma before "then".
So, I would write these sentences as:

If I pay according to the payment arrangement plan, then I will be given ten per cent off.
If you keep your promise and make payments according to the payment arrangement plan, then you will be eligible for ten per cent off.

Finally, you could always write "ten percent" as "10%", which many people would prefer.