Hello, I will try to answer your questions. Here is the screen of the Disc Layout Editor when I add two files. As can be seen, the size shown in the Explorer window is OK but the size in the Imgburn calculator window is changing Kb by Bytes.
And here is the Imgburn log
I 17:22:02 ImgBurn Version 2.5.7.0 started!
I 17:22:02 Microsoft Windows XP Professional (5.1, Build 2600 : Service Pack 3)
I 17:22:02 Total Physical Memory: 3
I 17:22:03 Initialising SPTI...
I 17:22:03 Searching for SCSI / ATAPI devices...
I 17:22:06 -> Drive 1 - Info: TSSTcorp CD/DVDW SH-S182M SB06 (F:) (ATA)
I 17:22:06 Found 1 DVD±RW/RAM!
I 17:22:59 Operation Started!
I 17:35:40 Building Image Tree...
I 17:35:41 Checking Directory Depth...
I 17:35:41 Calculating Totals...
I 17:35:41 Preparing Image...
I 17:35:41 Checking Path Length...
I 17:35:41 Contents: 2 Files, 0 Folders
I 17:35:41 Content Type: DivX Video
I 17:35:41 Data Type: MODE1/2048
I 17:35:41 File System(s): ISO9660, Joliet, UDF (1.02)
I 17:35:41 Volume Label: [Not Configured]
I 17:35:41 Size: 724
I 17:35:41 Sectors: 353
I 17:35:41 Image Size: 724
I 17:35:41 Image Sectors: 353
I 17:35:41 Operation Successfully Completed! - Duration: 00:00:00