ui-grid(x) with margin in second position

examples.scss

.examples {

 @include ui-grid;
 @include ui-grid(2);
 @include ui-grid(flip);
 
 @include ui-grid(2, 2.5%, 60%, 40%);
 @include ui-grid(2, 2.5%, 60%, 40%, flip);
 
 @include ui-grid(3);
 @include ui-grid(3, 2.5%);
 @include ui-grid(3, 5%, 20%, 60%, 20%);
 
 @include ui-grid(4);
 @include ui-grid(4, 2.5%);
 @include ui-grid(4, 5%, 10%, 40%, 25%, 25%);
 
 @include ui-grid(5);
 @include ui-grid(5, 2.5%);
 @include ui-grid(5, 5%, 20%, 40%, 10%, 10%, 20%);
 
}

ui-grid.scss

@mixin ui-grid($ui-grid-num: 2, $margin-r:5%, $width-1: 0%, $width-2: 0%, $width-3: 0%, $width-4: 0%, $width-last: 0%  ) {
    
	@include pie-clearfix;
	//Reference variable. Gets dicy when math placed in @for function
	$ui-grid-num-less-one: $ui-grid-num - 1;

	//Flip functionality
	//Supports flipping any ui-grid(2...)
	//@include ui-grid(2, flip); ui-grid(flip); ui-grid(2, 5%, 40%, 60%, flip);
	$flip: false;
	$var-list: $ui-grid-num, $margin-r, $width-1, $width-2, $width-3;
	@each $var in $var-list {
		@if $var == flip {
			$flip: true;
		}
	}
	@if $ui-grid-num == flip { $ui-grid-num: 2; }
	@if $margin-r == flip { $margin-r: 5%; }
	@if $width-1 == flip { $width-1: 0%; }
	@if $width-2 == flip { $width-2: 0%; }
	@if $width-3 == flip { $width-3: 0%; }
	//eo flip functionality

	//Default values given no supplied values
	@if $width-1 == 0% { $width-1: 100% / $ui-grid-num; }
	@if $width-2 == 0% { $width-2: 100% / $ui-grid-num; }
	@if $width-3 == 0% { $width-3: 100% / $ui-grid-num; }
	@if $width-4 == 0% { $width-4: 100% / $ui-grid-num; }
	@if $width-last == 0% { $width-last: 100% / $ui-grid-num; }

	//width-last needs to be determined no matter what, in case it's not supplied
	//Technically, you don't even need to supply the width of the last column anymore
	@if $ui-grid-num == 5 { $width-last: 100% - $width-4 - $width-3 - $width-2 - $width-1; }
	@if $ui-grid-num == 4 { $width-last: 100% - $width-3 - $width-2 - $width-1; }
	@if $ui-grid-num == 3 { $width-last: 100% - $width-2 - $width-1; }
	@if $ui-grid-num == 2 { $width-last: 100% - $width-1; }

	//ui-block-1 is a nice given
	> .ui-block-1,
	> .ui-block.first {
		width: $width-1 - ($margin-r/$ui-grid-num);
		@if $flip == true {
			@include float-right;
		} @else {
			@include float-left;
			margin-right: $margin-r/($ui-grid-num - 1);
		}
	}

	//ui-block-2 through x, whatever necessary
	$widths-list: $width-1, $width-2, $width-3, $width-4;
	@for $num from 2 through $ui-grid-num-less-one {
		$width: nth($widths-list, $num);
		> .ui-block-#{$num} {
			width: $width - ($margin-r/$ui-grid-num);
			@include float-left;
			margin-right: $margin-r/($ui-grid-num - 1);
		}
	}	

	//ui-block-(last) derived
	> .ui-block-#{$ui-grid-num},
	> .ui-block.last {
		width: $width-last - ($margin-r/$ui-grid-num);
		@if $flip == true {
			@include float-left;
		} @else {
			@include float-right;
		}
		margin-right: 0;		
	}
}