My wife accidentally overstayed around 17 days (I know

I understand if she's successful the counter on the 5 years route starts again. What is not 100% clear is if she is not granted the 5 year, but the 10 year again, does the counter also start again, or will the last 2.5 years still count towards the 10 years.
Believe it or not my solicitor cannot give me a definitive answer. Common sense says yes, but as it's different application she is not certain it will count as a continuation. She says you may not even have the answer until in 7.5 years you apply for the ILR and get granted/refused.
Anyone know any concrete info on this please.
Thanks in advance.
Steve.