如果我使用等于经常性付款金额的 INITAMT 进行请求，它会起作用。
但是，如果我尝试使用不同的 INITAMT（以及不同的 TAX）计费，我会收到此错误：
Tax calculation mismatch. The tax amount for the regular non-trial billing period is different than the sum of the tax for each item in the cart.
我的实际要求：
我有 4.84 欧元的首期付款，包括 0.84 欧元的增值税。
下个月的账单金额应为 25.09 欧元（包括 6.09 欧元增值税）。
我发送的请求基本上是这样的：
Method: CreateRecurringPaymentsProfile
"CURRENCYCODE":"EUR",
"INITAMT":4.84,
"TAXAMT":0.84,
"DESC":"Subscription",
"BILLINGPERIOD":"Month",
"BILLINGFREQUENCY":1,
"AMT":29,
"L_PAYMENTREQUEST_0_ITEMCATEGORY0":"Digital",
"L_PAYMENTREQUEST_0_NAME0":"Subscription",
"L_PAYMENTREQUEST_0_AMT0":29,
"L_PAYMENTREQUEST_0_TAXAMT0":6.09,
"L_PAYMENTREQUEST_0_QTY0":1
"PROFILEREFERENCE":"51a1f8f4732baf580a000031",
"PAYMENTREQUEST_0_INVNUM":"51a1f8f4732baf580a000031",
"INVNUM":"51a1f8f4732baf580a000031",
"PROFILESTARTDATE":"2013-06-26T11:59:12+0000",
和回应：
"TIMESTAMP":"2013-05-27T10:55:46Z",
"CORRELATIONID":"969d07e2cef8a",
"ACK":"Failure",
"VERSION":"74",
"BUILD":"5908853",
"L_ERRORCODE0":"10004",
"L_SHORTMESSAGE0":"Tax calculation mismatch.",
"L_LONGMESSAGE0":"Tax calculation mismatch. The tax amount for the regular non-trial billing period is different than the sum of the tax for each item in the cart.",
"L_SEVERITYCODE0":"Error"
我想使用INITAMT值来执行此操作，以便用户可以在 Paypal 私人区域中看到两次购买相关（即：带有初始付款的订阅）。
否则，我将不得不为初始付款进行单独的 DoExpressCheckout。