Dear,
No, records in infocube and aggregates will differ. If you see records in infocube using listcube OR directly from RSA1, it will show you individuals lines with characteristics and key figures as they have been loaded (You can though see aggregated data also using DB aggregation option on screen when you want to see data in cube).
you can understand aggregates data as summed up data based on characteristics that you have brought in while creating aggregates.
Aggregates are the way to enhance performance of query based on frequently used characteristics used to display data in query. Also when you compress requests in cube, this is also one of the example where individual requests are compressed, key figures are aggregated.
Thanks & Regards,
M