Sdelete overwrite function should avoid the letter Z as an extension overwrite function

Question

The Sysinternals Sdelete utility has a secure overwrite function which will rename the files 26 times wherein each character in the file name will go from foo.bar to AAA.AAA, then BBB.BBB, and so on. However, if the file being overwritten happens to have a five letter extension, then on the last overwrite, it will have the extension of .ZZZZZ, which is the signature of a Ransomware file and the sdelete.exe is terminated by the Antivirus application. The file is now permanently stuck on the file system, and looks like a ransomware file. Nothing can touch it until you stop the Antivirus application and manually delete the .ZZZZZ file. Can this be fixed in the sdelete overwrite function to skip the 26th overwrite as a "Z" and make it another character that does not appear to be ransomware?