Issue setting data in a device using API with PHP

I am trying to set data in a device using API with PHP. The following code works fine and sets the value of the resource (‘starter’) to 1 when called.

<?php
$device = 'Mydevice'; // the device id
$user = 'user1'; // your user id
$resource = 'starter'; // your resource name like 'led', 'relay', and so on.
$authorization = 'authToken'; // a device access token for controlling all or this resource only
$go = 1; // setting  value 1  for this counter

$url = "https://api.thinger.io/v2/users/{$user}/devices/{$device}/{$resource}?authorization={$authorization}";

$data = array(
    'in' => $go 
);

$options = array(
  'http' => array(
    'method'  => 'POST',
    'content' => json_encode( $data ),
    'header'=>  "Content-Type: application/json\r\n" .
                "Accept: application/json\r\n"
    )
);

$context  = stream_context_create( $options );
$result = file_get_contents( $url, false, $context );
$response = json_decode( $result );
?>

However, I am unable to set more than 1 value in a resource.
example:
esp8266 is sending 2 sensors data as:

          thing["usage"] >> [](pson & out) {
          out["Wh1"] = Wh1;
          out["Wh2"] = Wh2;
          };

I tried the PHP code below to change the values of “Wh1” and “Wh2” but it does not work. Any advice is appreciated.

<?php
$device = 'Mydevice'; // the device id
$user = 'user1'; // your user id
$resource = 'usage'; // your resource name like 'led', 'relay', and so on.
$authorization = 'authToken'; // a device access token for controlling all or this resource only

$uso = array('Wh1'=> 8,'Wh2' => 99); // trying to set 2 values for this counter

$url = "https://api.thinger.io/v2/users/{$user}/devices/{$device}/{$resource}?authorization={$authorization}";

$data = array(
    'in' => $uso 
);

$options = array(
  'http' => array(
    'method'  => 'POST',
    'content' => json_encode( $data ),
    'header'=>  "Content-Type: application/json\r\n" .
                "Accept: application/json\r\n"
    )
);

$context  = stream_context_create( $options );
$result = file_get_contents( $url, false, $context );
$response = json_decode( $result );
?>

Waiting to have a solution, I am (as a temporary workaround) sending the data separately and using 2 separate resources.

          thing["usage1"] >> [](pson & out) {
          out["Wh1"] = Wh1;
          };
         thing["usage2"] >> [](pson & out) {
          out["Wh2"] = Wh2;
          };