Timeline and timekeeping in Once Upon a Time

OK, its time to clear some stuff up here concerning time keeping.

Certain stories take place upwards of 300 years or more before certain other stories in the Enchanted Forest timeline.

Elsa was a prisoner within the urn for 9 weeks due to time travel occuring with Emma Swan and Killian Jones arrival in the enchanted forest. Had Killian not moved the urn to begin with, Elsa would still be trapped in the enchanted forest through season four to begin with. Thanks to time travel, Elsa was only in the urn for 9 full weeks before arriving in Storybrooke after the second curse was cast.

Others say that elsa was in the urn for several years, this is an impossiblity due to the time travel when Emma and Killian showed up in the EF before Emmas parents ever met to begin with

I do not see how people are completely ignoring the time travel element and thinking otherwise. It was in the SAME DAY that Elsa was entrapped within the urn by her sister that Ingrid removed Elsa's memorie of the event, and froze the Kingdom of Arendelle before fleeing to get the hat and summon Rumple to do the trade as planned. Elsa was then in Storybrooke for three weeks of October 2013, it was not until 27 November 2013 when Frozen came to theatres. Therefore Elsa was only away from Arendelle for 90 days, but to her kingdom she was gone for 30 years but the kingdom was frozen in time