PSW visa decision extebded for further enquiry

[pumnoo]

Dear all,
i m an ACCA student. in Feb 2010 i extended my visa on ACCA basis. i recieved extention till Oct 2011. in June 2010 i finished my foundation stage of ACCA. In July i started my MBA in line with rest of the papers of ACCA. because i was doing MBA from the same college therefore i had not needed to inform Home Office about the new cource. so till June 2011 i finshed my theory part of the MBA degree. and in October 2011 i submitted my dissertation. in the mean time my visa was expiring in Oct 11. upto that point two papers of my ACCA was left on that basis i applies for extension for next 6 six months which i recieved as well. In Jan 2012 i have recieved the result of my MBA dissertation which I pass. i had already booked my PEO PSW extention appointment on 1st Feb. the document which i had for proof of the study was one email of result confirmation sent by the university to my college and one letter from my college as a confirmation ( btw my college is highly trusted college). in interview visa officer argued that you have been getting visa extension on ACCA and out of no where you are showing your MBA degree. therefore we need to extend our enquiry and will confirm from the University about your study. additionally i m in UK on student visa from last 8 and half years and this extension would complete my 10 yrs duration for being eligible for indefinite stay in UK. visa officer was also aware of it and mentioned as well. therefore she became more curious about it. now my question is, how long does home office normally take to get confirmation from the university of Wales and make the decision about the extension.and how accurate and promptly the University-officials correspond with Home office enquiries. and is there anything else particular to my case , anyone want to share with me . i could not sleep whole night in this tention.
Kind regards
Pumnoo