just worried

[Terpe]

..... I wonder if the basis should be the date the application was submitted or when was the visa released. Your clarification on this matter will be greatly appreciated.

The basis is made solely on the date of visa application submission.

Here's what UKBA state:-

Those who, before 9 July 2012, have applied for initial or further leave under the rules in force prior to that date will, if they qualify for it, be granted leave under those rules and will continue to be dealt with under those rules through to indefinite leave to remain if they qualify for it..