User talk:2606:4580:2:0:90CD:7A27:9BD1:81C3

Apparently "targetted" is not a valid word, and it is always "targeted", regardless of US/UK, according to Future Perfect: http://www.future-perfect.co.uk/grammar-tip/is-it-targetted-or-targeted/

They claim: The official requirements are that we ‘double a single consonant letter at the end of any base where the preceding vowel is spelled with a single letter and stressed’.

It is true to say that there is usually no doubling when the preceding vowel is unstressed (‘enter’ becomes ‘entering/entered’; ‘visit’ becomes ‘visiting/visited’) or when the preceding vowel is written with two letters (‘dread’ becomes ‘dreading/dreaded’).