Set Item Price Fields

I am trying to set the price level field values on an inventory item on a SuiteScript. I load the record but cannot seem to set the price fields. Yes, I know its unsupported, but what Am I doing wrong?

Code is as follows and I thought fields were "priceprice_1_1, priceprice_1_2, etc..

// Get id of the item
var id = record.getLineItemValue('item', 'item', i);
// Load the Item
var item = nlapiLoadRecord('inventoryitem', id);
var basePrice = 10; // Just picked 10 to test
// Set the price
item.setFieldValue('priceprice_1_1', basePrice );

Thanks for any help!

Robert