I believe the prefix that is specified in the Recording Setup (in your case, "930service") always has to be first. You could change the formatting to the following:
{0}_{1:yyyyMMdd_HHmm.ss}

This would give you:
930service_20170402_0929.58

Assuming your prefix stays the same, that should be more sortable than the default. I hope that helps!

I have struggled with the Recording Filename Format. I post my recordings to our website and my PHP code needs the filename to be in the following format:
2018-05-27_Church Name ~ City, State_May Services_Sunday Morning_Preacher Name_Message Title_0.mp4

Under Recording Setup my Filename is:
C:\Users\steve\PilgrimRestLittleRock.org\www\videos\Pilgrim Rest Baptist Church~Little Rock, Arkansas.mp4

Under Settings-->Recording as follows:
Default Folder for Recordings:
C:\Users\steve\PilgrimRestLittleRock.org\www\videos
Filename Format:
{1:yyyy-MM-dd_}{0}{1:_hh-mm-ss tt}

An example vMix Recording file looks like this:
2018-06-01_Pilgrim Rest Baptist Church~Little Rock, Arkansas_04-01-18 PM.mp4
I have the following line ready for copy and paste:
June Services_Sunday Night_Pastor Steve Westbrook_Real Reasons To Rejoice_0.txt
So after the copy and paste I have a file ready to upload to the website:
2018-06-01_Pilgrim Rest Baptist Church~Little Rock, Arkansas_June Services_Sunday Night_Pastor Steve Westbrook_Real Reasons To Rejoice_0.mp4

I hope this helps someone else who might be struggling with the Filename Format in vMix.

Steve Brown