Tariff Bleu

Can anyone shed light on why/how my tariff bleu hours appear to have changed? For the past 10 years they have been 2pm-5pm and 2am -7am. Today I heard the timer click off at 9pm. I have no idea how the little switch in the fuse box works, just knew it clicked on and off at the same time every day. Someone told me I was lucky to have the afternoon hours and that most people on tarrif bleu only had the one solid 8 hour low period. Can it be changed remotely by EDF or externally at the outside box?