The Bulk Hours Editing tool lets you view and optionally edit hours records for many volunteers at once without opening up individual profiles.
Put in your filters on Jobs, Locations, etc. then click Refresh.
This tool can be configured with "inline" editing:
Inline editing: You'll edit assignments by clicking directly on them in the listing (you can change the Date, Start, Duration, delete the assignment, Distance and Comments). You have to click Save at the bottom for any of your changes to take effect.
Simple editing: If you're not editing inline, you'll get an Edit link for each assignment, and clicking Save in that popup editor saves the assignment.