fix: wording

05.md

@@ -32,7 +32,9 @@ The wallet `Alice` includes the following `PostMeltQuoteBolt11Request` data in i
 }
 ```
 
-Here, `request` is the bolt11 Lightning invoice to be paid and `unit` is the unit the wallet would like to pay with. `amount` is an integer or null, representing the amount to be paid. If the invoice already defines an amount, the amount in the PostMeltQuoteBolt11Request **MUST** match the amount in the invoice exactly. The request may only be in amountless invoice if support for amountless invoices is signaled in the `MeltMethodSettings`.
+
+Here, `request` is the bolt11 Lightning invoice to be paid and `unit` is the unit the wallet would like to pay with. `amount` **MAY** be passed to pay amountless bolt11 invoices. For bolt11 invoices with an amount, the `amount` field **MUST** be equal to the amount of the bolt11 invoice if included. The request **MAY** be an amountless invoice only if support for amountless invoices is signaled in the `MeltMethodSettings`.
+
 
 The mint `Bob` then responds with a `PostMeltQuoteBolt11Response`: