CoS duration and IHS fee

Hi everyone,

I’ve been offered a job to come back to the UK by my previous employer. They had recently obtained a sponsor license and are new to sponsoring a worker. They want me to start as soon as possible and are ready to pay for the priority visa application. My HR informed me they have applied for a defined CoS with start date as 15/07/2024 and end date as 15/07/2026. Now I have couple of questions,
1. Are these dates considered as more than 2 years? If so would I have to pay IHS fee for 3 years or do I have to just pay for the extra one day? If I do have to pay for 3 years, can they add a sponsor note with amended date?

2. Are my dates realistic or should I ask them to change the dates to be more conservative in case there’s a delay in issuing CoS/Visa?