Hey FatFreek 2005!
If you work on KIngdom Hall construction, are you allowed to count your time in lieu of field service?
Yes, and no:
REGULAR PIONEERS - BoE letter 25 August 2014 'Re: Regular pioneers', paragraphs 14 to 16
https://drive.google.com/file/d/0BwqmWMK7dwtlb0JteEJTT3RmeTg/view
PUBLISHERS - BoE letter 7 November 2008 'Re: Field service reports', last pararaph
https://drive.google.com/file/d/0BwqmWMK7dwtlaGUzSkthUGhJak0/view
On the back of the Report they should write a brief note describing the additional theocratic responsibilities they cared for that month, no hour figure needs to be given - this can then be written on the Publisher Record Card under the 'Remarks' column (interestingly the new Report forms have a 'Comments' section on the front nowadays)
Not sure about Auxiliary Pioneers, but I'd suspect they'd be covered by the 'Publisher' procedure - though I'd suspect the BoE would show consideration for short-term short-fall in hours due to theocratic activity if the publisher was a regular auxiliary pioneer.