Using gform_post_render slows down my Form

Im 100% sure I've written terrible jQuery and I shouldn't be let near a keyboard again lol.

Here is my form http://designfitz.com/product/thesis/

when you click 'Front & Spine' radio button it takes aaages to change, but if i remove this code its fixed, I'm sure im using gform_post_render wrong. Any ideas how I could tidy up this code? and use gform_post_render correctly?

// Total Books for Delivery 1

    jQuery(function() {
    firstdeliverytotal();
    }
        );
    jQuery(".steve select").change(function() {
    firstdeliverytotal();
    jQuery(document).trigger('gform_post_render', [7,1])

    }
                               );

    function firstdeliverytotal()
    {
    var totalPoints = 0;
    jQuery('.steve option:selected').each(function(){
      totalPoints = parseFloat(jQuery(this).text()) + totalPoints;
    }
                                        );

    jQuery("#input_7_16").val(totalPoints);
    jQuery(document).trigger('gform_post_render', [7,1])

    }
    ;

    // Total Books for Delivery 2

    jQuery(function() {
    seconddeliverytotal();
    }
        );
    jQuery(".smith select").change(function() {
    seconddeliverytotal();
    jQuery(document).trigger('gform_post_render', [7,1])

    }
                               );

    function seconddeliverytotal()
    {
    var totalPoints2 = 0;
    jQuery('.smith option:selected').each(function(){
      totalPoints2 = parseFloat(jQuery(this).text()) + totalPoints2;
    }
                                        );

    jQuery("#input_7_119").val(totalPoints2);
    jQuery(document).trigger('gform_post_render', [7,1])
    }
    ;

    // Total Hardbacks for Delivery1
    jQuery(function() {
    hardbacksdelivery1();
    }
        );
    jQuery("#input_7_106,#input_7_105").change(function() {
    hardbacksdelivery1();
    jQuery(document).trigger('gform_post_render', [7,1])

    }
                               );

    function hardbacksdelivery1()
    {
    var totalhardbacks1 = 0;
    jQuery('.hardback1 option:selected').each(function(){
      totalhardbacks1 = parseFloat(jQuery(this).text()) + totalhardbacks1;

    }
                                        );

    jQuery("#input_3_11").val(totalhardbacks1);
    jQuery("#input_7_118").val(totalhardbacks1);
        jQuery(document).trigger('gform_post_render', [7,1])
    }
    ;

    // Total Hardbacks for Delivery2
    jQuery(function() {
    totalhardbacks2();
    }
        );
    jQuery("#input_7_109,#input_7_108").change(function() {
    totalhardbacks2();
    jQuery(document).trigger('gform_post_render', [7,1])

    }
                               );

    function totalhardbacks2()
    {
    var totalhardbacks2 = 0;
    jQuery('.hardback2 option:selected').each(function(){
      totalhardbacks2 = parseFloat(jQuery(this).text()) + totalhardbacks2;

    }
                                        );

    jQuery("#input_7_123").val(totalhardbacks2);

        jQuery(document).trigger('gform_post_render', [7,1])
    }
    ;