calculating the tier 4 time is very easy and not at all difficult. i can help you to do it, if you post all your course start dates and end dates and course level and institution.
please follow pages 55-61 of the link below for detailed guide.
and for calculating the time please refer specifically to pages 60-61.
tier 4
https://www.gov.uk/government/uploads/s ... .0_EXT.pdf
it is not difficult at all, and i do not think you needed to have filed a SAR to know the time left, as it is your responsibility to do it.
FLR (o) as said by the guidance in your case is 'Other purposes or reasons not covered by other application forms'.
the first and foremost question will be that what was the need to apply for a FLR (o)?
if you did not get admission on the 60 days letter you could have gone back and applied. for flr to be granted there need to be very solid and compassionate reasons, which you may or may not have.
provided you have 1 year left for your 10 years, even if you play by the system by sending the application, getting refused, appealing, again appealing. it will not give you 1 year, as flr turnaround times are faster and they will try to dismiss your appeal as you will be nearing the 10 years time.
flr o is considered to by bad for the immigration history because it shows the desperation to stay. once refused you will have to mention this in all visa applications you do for good number of years, for example for countries like, Australia, Canada, US and etc. and moreover your passport will be stamped with a refusal number which the immigration officers know is of refusal. any refusal from any country for a visa does not leave a good impression. its just like damaging your credibility to get a visa. even in the future you will have trouble getting the UK visa because you will be refused questioning your intention to return.
flr (o)
https://www.gov.uk/government/publicati ... -form-flro