How can I get a second x axis in my guide gui?

I have a simple gui that is plotting 5 different plots from the same set of data. The x axis are all in position (mm), with different forces or torque as the y axis (see picture). I would like to add another x axis to the top two plots that are based on time (sec). (my current code affects the "green" plot "Average X-Force plot)

I am currently using the following code

% X Force Plot  ONE OF MY PLOTS
    axes(handles.xplot);                                                            % Select the plot that I want to visualize my data
    cla;                                                                            % clear the axes incase something was left
    handles.xplot = gca;                                                            % get all of the values of the axes
    ax1_pos = handles.xplot.Position;                                               % get the position of the main axis
    ax2 = axes('Position', ax1_pos, 'XAxisLocation', 'top', 'Color', 'none');       % Set the second axis
    
    for i = 1:revs-1                                                                % plot a point per "rotation" per my application
        s = handles.dw.DefectiveWelds{1,1}{1,weldnum}{1,17}(i,1);                   % start of desired part of data set (I added it to my handles structure)
        e = handles.dw.DefectiveWelds{1,1}{1,weldnum}{1,17}(i+1,1);                 % end of desired part of data set (to calculate the mean of the temperature and forc)e
        time = handles.dw.DefectiveWelds{1,1}{1,(weldnum)}{1,1}(s,1);               % Time vector of the data
        xpos = handles.dw.DefectiveWelds{1,1}{1,(weldnum)}{1,2}(s,1);               % x position vector of the data
        avex = mean(handles.dw.DefectiveWelds{1,1}{1,(weldnum)}{1,10}(s:e,1));      % Average x force vector of the data
        temp = mean(handles.dw.DefectiveWelds{1,1}{1,(weldnum)}{1,6}(s:e,1));       % Temperature vector of the data
        
        plot(xpos ,avex,'*','Color',[76/255,153/255,0])                             % plot the x position by the average x force in green
        hold on                                                                     % Hold on for second axis
        plot(time ,avex,'Parent', ax2, 'Marker','*', 'Color', [76/255,153/255,0])   % Plot the same x force but by time (top axis)
        hold on                                                                     % Hold on to wait and plot the next point
    end
    
   title('Average X-Force (N)')                                                     % title for the plot
   handles.xplot = gca;                                                             % Set the plot values for the gui 
   guidata(hObject,handles);                                                        % update the values
   

Thanks in advance

John