Interesting, did you have to do much with the your backup files in terms of figuring out which one to use? I don't know how I could write this more concisely in T-SQL.

#Find the latest FULL and DIFF backup.    

    $FullBackup = Get-Childitem Microsoft.PowerShell.Core\FileSystem::$PartialPath $fullExtension | Where-Object {$_.Name -match $Row[2] + "_[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]*" } | Sort-Object LastWriteTime -descending | Select-Object -FIRST 1
    $DiffBackup = Get-Childitem Microsoft.PowerShell.Core\FileSystem::$PartialPath $diffExtension | Where-Object {$_.Name -match $Row[2] + "_[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]*" } | Sort-Object LastWriteTime -descending | Select-Object -FIRST 1