Yes, of course. It is possible to get displayed only files of different size and/or unique files.
I suppose UltraCompare v16.00 is already used by you.
With a Folder Compare session already opened, click with using ribbon mode on ribbon tab Home on Set compare options. On using toolbar/menu mode, click in menu Session on Session Properties. In the opened dialog there is the setting Ignore timestamp differences which should be checked to compare files only by file size with ignoring file date/time.
In this dialog you can also check/uncheck the Display and Filter options. Check Hide same files and on running a recursive folder comparison also Hide same folders to get displayed only files existing in both directories with different size and unique files which exist either only in left or only in right directory (tree).
Click on button Ok and Run in left bottom corner of the dialog window.
The Display and Filter options can be also changed later after folder comparison already done. Open Legend & Filters view which is usually docked in auto-hide mode on left or ride side by moving the mouse pointer over the tab of this view and check/uncheck the options. This view can be also opened in ribbon mode by checking on ribbon tab Layout the item Legend & Filters and in toolbar/menu mode by clicking in menu View on menu item Show Legend & Filters.
In ribbon mode there is on ribbon tab View also the item Filter with on click on the down arrow opens a pop-up menu with the options to hide/unhide files/folders like on Legend & Filters view. The filter options are of course also available in toolbar/menu mode in menu Options in submenu Folder Mode Filters.
Last but not least the default settings for new folder comparisons can be also defined in Configuration opened in ribbon mode with a click on ribbon tab Home on item Settings (top right item) and in toolbar/menu mode in menu Options on menu item Configuration.
Double click on a file with different size to start in same instance of UltraCompare a text comparison of the two files.
For more help, please open help of UltraCompare and read the appropriate help pages.