jQuery paging - number of pages is wrong

Question

I'm trying to make a paging functionality in a rss parser. It's almost working. Only the last page is wrong. See fiddle here. The last page displays 11-10. Why is that? There are currently 10 items in the feed, so in this example there should be only two pages, not three - and on page number two, the "next" button should be hidden.

Is this where something is wrong?

if (numEntriesReturned+1-oRssConfig.contempOffset>0 && oRssConfig.contempOffset<100-oRssConfig.maxItems) $('#btnNext').css("display", "block");
    else $('#btnNext').css("display", "none");

Answer 1

After many hours, I re-wrote the script completely. This should work to load & paginate the RSS feed using Zazar's zRSSFeed plug-in. I commented most functions so you can see and understand whats going on, well, hopefully!

Features:
Easily choose 'Feeds Per Page' to display.
Easily enter the link to the RSS Feed.
Next & Previous Buttons appear/disappear when needed.
Displays Feed Count automatically on each page. Example: '1 of 5'

Check out this Fiddle to see it in action!
Any questions?

JQuery Script

// Editable Values
var feedlink = 'http://feeds.reuters.com/reuters/oddlyEnoughNews'; // Set Feed Location
var fpp = 4; // Choose how many feeds per page to display (fpp = Feeds Per Page)
var feedview = '#RSSview'; // Choose where to diplay the RSS Feed

// Initial Variables ( Do Not Edit )
var feeds = null; // Variable to hold total feed count
var totalpages = null; // Variable to hold total pages
var currentpage = null; // Variable to hold Current Page being Displayed
var lastpagefeeds = null; // Variable to hold Amount of Feeds on the Last Page
var firstof = null; // Variable to hold First Feed Display - Example: 3 of ?
var lastof = null; // Variable to hold Last Feed Display - Example: ? of 10
var feedoffset = 1; // Set Initial Feed Offset

///////////////////
// RSS Functions //
///////////////////

// Calulate Feed Count Display
function displayfeedcount(){
    // Set 'First Of ???'
    firstof = feedoffset;
    // Set '??? of Last'
    if(currentpage == Math.ceil(totalpages)){ lastof = feeds; }else{ lastof = (firstof + fpp) - 1;}
    $('#offsetDispl').html( firstof + ' of ' + lastof); // Display Feed Count ' First of Last'
}

// Load Initial Feeds on Page 1
function initialfeeds(){
    $(feedview).rssfeed( feedlink , { limit: fpp , offset: 0 }); // Load Initial Set of Feeds
    currentpage = 1; // Set Current Page to 1
    displayfeedcount(); // Trigger the Display of Feedcount - Example: '1 of 5'
}

// Calculate Total Pages
function calculatepages(){
    totalpages = feeds / fpp; // Total Page Calculation
    console.log( 'Total Pages: ' + totalpages); // Log - For Testing Purposes Only - Delete if Desired
    initialfeeds(); // Trigger Initial Display of Feeds
}

// Determine if the NextBtn should be shown on load
function showbuttons(){
    if ( feeds > fpp ){ $('#btnNext').show(); } // Evaluate 'Next Button' Visibility
}

// Determine Total Feed Count
function feedcount() {
    feeds = arguments[1]; // Set Feed Count to Variable 'feeds'
    console.log( 'Total Feeds: ' + feeds ); // Log - For Testing Purposes Only - Delete if Desired
    showbuttons(); // Trigger Initial Button Display
    calculatepages(); // Trigger Total Page Calculation
}

// Function to Show Next Page
function nextpage(){
    currentpage = currentpage + 1; // Set New Current Page
    feedoffset = feedoffset + fpp ; // Set New Feed Offset   
    console.log('Current Page is: ' + currentpage);  // Log - For Testing Purposes Only - Delete if Desired
    console.log('Feed Offset is: ' + feedoffset );  // Log - For Testing Purposes Only - Delete if Desired
    $(feedview).rssfeed( feedlink , { limit: fpp , offset: feedoffset }); // Load Next Set of Feeds
    if( currentpage >= totalpages ){ $('#btnNext').hide();} // Evaluate 'Next Button' Visibility
    if( currentpage > 1){ $('#btnPrev').fadeIn('250');} // Evaluate 'Previous Button' Visibility
    displayfeedcount(); // Display Feed Count ' ??? of ??? '   
}

// Function to Show Previous Page
function prevpage(){
    currentpage = currentpage - 1;  // Set New Current Page
    feedoffset  = feedoffset - fpp ; // Set New Feed Offset
    console.log('Current Page is: ' + currentpage);  // Log - For Testing Purposes Only - Delete if Desired
    console.log('Feed Offset is: ' + feedoffset );  // Log - For Testing Purposes Only - Delete if Desired
    $(feedview).rssfeed( feedlink , { limit: fpp , offset: feedoffset });
    if( currentpage <= totalpages ){ $('#btnNext').fadeIn('250');} // Evaluate 'Next Button' Visibility
    if( currentpage <= 1){ $('#btnPrev').hide();} // Evaluate 'Previous Button' Visibility
    displayfeedcount(); // Display Feed Count ' ??? of ??? '
}

// Bind Previous and Next Button Clicks
$('#btnPrev').on('click', prevpage); // Bind the PrevPage Function
$('#btnNext').on('click', nextpage); // Bind the NextPage Function

// Retrieve Total Feeds
$('#hidden').rssfeed( feedlink , {}, feedcount);
// Make sure this divider exists on the page body >>>  <div id="hidden" style='display:none;'></div>