Lighting schedule issues? Help?

Heya everyone.

Iv had my plant on 12/12 for the last 5 days but for the last two day my bloody android phone alarm has been playing up so iv missed the light switch on time. yesterday it had an extra hour of darkness and today it had an extra 3 hours of darkness. Its usually 10am to 10pm when lights are on. What im worried about is the stress this might cause? Im thinking of going back to 18/6 or 16/8? Because i did top my plant yesterday and i think the veg might be good in recovery for her. Its not mature yet so its not flowering.

Any ideas? or should i just stick to 12/12 and turn off at 10pm and stay where i am?

Note: i have a new alarm app lol. which does work

Invest $10 , maybe a little less and buy a timer . Set timer for the time you want ON and time OFF . set it and forget it. One of the best investments you can make for your grow op.