Continuous 5 year period eligibility for ILR

Hi everyone, I just wanted your thoughts or advice on my current situation. I am due to apply for ILR but am 2 months short as the Home Office stamped the extension date earlier. Let me explain.
I was on permit-free training visa (for 2 years) and in May 2006, I applied for HSMP approval. I received this in July 2006 but for various reasons could not apply for HSMP visa. Ultimately, I applied for this in October 2006 and received HSMP from November 2006 for 2 years (until November 2008).
I then applied for extension under the Tier 1 General category rules in August 2008 (as HSMP was abolished). The reason I applied in August (instead of October) was because I had to travel in December and needed my passport in time.
I then received the extension stamped from September 2008 until September 2011 (instead of November 2008 until November 2011). Along with this, I also received a letter from the Home Office stating that this would be sufficient for ILR application 'towards settlement as per the current threshold of 5 years'. It also advises to attach the letter along with my ILR application.
I am a bit concerned about my eligibility for ILR application because I have completed a little less than 5 years (58 months). I have consulted a solicitor and he has advised it would not be a problem.
Has anyone else been in a similar situation? Would this pose a problem for ILR application? Thanks everyone for your advice.

See also Initial HSMP + TIER1( under HSMP JR) + possible extension

sushdmehta wrote:See also Initial HSMP + TIER1( under HSMP JR) + possible extension

Thanks for this Sush. Does this mean that I have to send my passport along with my dependents' passports for extension to Oliver by attaching the letter from Katy?