JB007, you are right about the increase in duty hours, however in Ryanairland things work differently (apparently).
A colleague on standby was phoned at home and called out for a duty later on that day involving 4 sectors and a long'ish duty period. When asked what time he would be expected back and raising FTL concerns, he was told that half (correct) of his SBY from when it started at 0400Z till the time he was callled by the crewing department (incorrect) would be added to his duty. In other words, you’re only on SBY till the phone rings ! That is the Ryanair position apparently. As usual Ryanair's ops manual is unclear on any issue like this, where the company can manipulate it to its advantage. And once again the spineless individuals in the IAA just sit on the sidelines and take no action.
At least most UK operators (operating under CAP 371) have it in black and white :-
12.3 If a crew member is called out from standby, the standby duty will cease when that individual reports at the designated reporting point.