PDF printing Applescript stopped working correctly

Hi,
I used to use the batch print function in Adobe Acrobat Pro to print a folder full of pdfs. When I did this, the items in the folder would not print in order. That is if I had Item A, Item B, Item C, Item D… the order of printing might be Item B, Item D, Item C, Item A.

I wrote an applescript so that pdfs would print in alphanumerical order. Here it is:

property FileTypeList : {"PDF"}
property extension_list : {"pdf"}
global this_info

on run
	display dialog "Don't doubleclick me! Drop a folder on top of me to execute program!" buttons {"OK"}
end run

on open these_items
	
	with timeout of 600 seconds
		repeat with i from 1 to the count of these_items
			set this_item to (item i of these_items) as alias
			set this_info to info for this_item
			if folder of the this_info is true then
				process_folder(this_item)
			else
				try
					set this_extension to the name extension of this_info
				on error
					set this_extension to ""
				end try
				try
					set this_filetype to the file type of this_info
				on error
					set this_filetype to ""
				end try
				if (folder of the this_info is false) and (alias of the this_info is false) and ((this_filetype is in the FileTypeList) or (this_extension is in the extension_list)) then
					process_item(this_item)
				end if
			end if
			
		end repeat
	end timeout
end open

on process_folder(this_folder)
	set these_items to list folder this_folder without invisibles
	repeat with i from 1 to the count of these_items
		set this_item to alias ((this_folder as Unicode text) & (item i of these_items))
		set the this_info to info for this_item
		if folder of the this_info is true then
			process_folder(this_item)
		else
			try
				set this_extension to the name extension of this_info
			on error
				set this_extension to ""
			end try
			
			try
				set this_filetype to the file type of this_info
			on error
				set this_filetype to ""
			end try
			if (folder of the this_info is false) and (alias of the this_info is false) and ((this_filetype is in the FileTypeList) or (this_extension is in the extension_list)) then
				process_item(this_item)
			end if
			
		end if
		
	end repeat
end process_folder

on process_item(this_item)
	tell application "Adobe Acrobat Pro"
		activate
		open this_item
		print pages active doc PS Level 3
		delay 0.5
		close active doc
		
	end tell
end process_item

For six months, it has worked as I wanted. PDFs would print in the order of ascendence as they appeared in the folder. Today, however, I printed a folder of about 90 pdfs, and they printed out of order. I thought that putting the items into a list, then using a repeat loop would force the items to print in order, but I must be wrong about that. Can anyone think of why this happened or how I might fix it?

There’s more:

I tried

tell application "Finder"
	set these_items to items of (choose folder)
	
end tell

and got a sort order such that

Item 3, Item 4, Item 5, Item 100, Item 11, Item 110

what I want, and what the finder Window shows is

Item 3, Item 4, Item 5, Item 11, Item 100, Item 110

Why does the Finder Window show the correct order of items, but the applescript does not?

I also tried:

ell application "Finder"
	set these_items to items of (choose folder)
	sort items of these_items by name
end tell

but got the same result. Argh!

Thanks.