H-Series ballast woes - should I convert to LED?

Our church installed thirteen 4-ft. ceiling fixtures about 5 years ago. Each fixture has (2) H-Series ballasts [EHDT832GU310] and (6) T8 tubes. They are switched and dimmed in banks of 3 or 4, using the control circuit feature (Terminals T1 & T2), and are used only about 10 hours per week. Thus far 6 of the 26 ballasts have failed - 23%.
1) Are these ballasts prone to failure and should we expect to see the remainder of them fail over the next 5 years?
2) Should we consider progressively replacing any failed ballasts with LED's, and how would that be done to maintain uniform dimming, etc.
Sincere thanks for any help!