CFHTTP based on PHP Example

I am trying to create reports in Stripe but their examples are PHP. I've had success with all their other functions I'm just stuck on reports. The PHP example is: 

POST 

/v1/reporting/report_runs

// Note that a live-mode API key is required.
\Stripe\Reporting\ReportRun::create([
  'report_type' => 'balance_change_from_activity.itemized.3',
  'parameters' => [
    'interval_start' => '1577865600',
    'interval_end' => '1580544000',
    'timezone' => 'America/Los_Angeles',
  ],
]);

My code looks like:

<!--- Data related to call --->
<cfset stripe_api_key = 'sk_live_XXXXXX' />
<cfset stripe_api_url = 'https://api.stripe.com/v1/' />
<cfset report_type = 'payout_reconciliation.summary.1' />
<cfset Interval_Start = #DateDiff("s", DateConvert("utc2Local", "January 1 1970 00:00"), Start)# />	
<cfset Interval_End = #DateDiff("s", DateConvert("utc2Local", "January 1 1970 00:00"), End)# />
<cfset timezone = 'America/New_York' />
<!--- Call --->
<cffunction name="createReport" access="private">
	<cfargument name="interval_start" type="numeric" required="true">
	<cfargument name="interval_end" type="numeric" required="true">
	<cfargument name="timezone" type="string" required="true" default="">
	<cfargument name="report_type" type="string" required="true" default="">
		
	<cfhttp url="#stripe_api_url#reporting/report_runs" method="POST" username="#stripe_api_key#" password="" charset="utf-8" result="report_result">
	   <cfhttpparam type="formfield" name="Report_Type" value="#arguments.report_type#" >
		<cfhttpparam type="formfield" name="parameters[interval_start]" value="#arguments.interval_start#" >
		<cfhttpparam type="formfield" name="parameters[interval_end]" value="#arguments.interval_end#" >
		<cfhttpparam type="formfield" name="parameters[timezone]" value="#arguments.timezone#" >		
	</cfhttp>	
	<cfif NOT isDefined("report_result.statusCode")>
		<cfthrow type='Stripe' errorcode="stripe_unresponsive" message="The Stripe server did not respond." detail="The Stripe server did not respond." />
	<cfelseif left(report_result.statusCode,3) NEQ "200">
		<cfreturn deserializeJSON(report_result.filecontent) />
	</cfif>
	<cfreturn deserializeJSON(report_result.filecontent) />	
</cffunction>

The request post body on Stripe:

{
  "Report_Type": "payout_reconciliation.summary.1",
  "parameters": {
    "interval_start": "1589256000",
    "interval_end": "1589342400",
    "timezone": "America/New_York"
  }
}

 It returns:

{
  "error": {
    "code": "parameter_unknown",
    "doc_url": "https://stripe.com/docs/error-codes/parameter-unknown",
    "message": "Received unknown parameter: Report_Type",
    "param": "Report_Type",
    "type": "invalid_request_error"
  }
}

I am guessing it's got to do with this part of the PHP which I don't understand:

I appreciate any help.....