ALTERNATIVE ARRANGEMENTS

No. The exchange rate should be the daily exchange rates published in the C series of  the Official Journal of the European Union, calculated over the corresponding reporting  period.
If no daily euro exchange rate is published in the Official Journal for the currency in  question, they must be converted at the average of the monthly accounting exchange  rates published on the European Commission website (InforEuro), calculated over the 
corresponding reporting period. To calculate the rate, the beneficiaries may use the editable charts on the ECB website 

http://www.ecb.europa.eu/stats/exchange/eurofxref/html/index.en.html

How to calculate the rate on the ECB website: 
Step 1 — Go to the ECB website. 
Step 2 — Click on the chart icon [ ] for the currency. 
Step 3 — Choose the ‘HTML5 version’ which appears under the name of the currency in the top-left corn
Step 4 — Insert the starting date of the reporting period in the field ‘from’ and the end date of the reporting period in the field ‘to’. The average for the period will appear above the chart.

Yes, although now they are referred as “alternative arrangements”. Only some elements can be derogated (chapter 14 of the Single Form)and refer to visibility and  communication activities, exceptional extreme operational conditions, country-specific  issues or other unforeseeable circumstances that arise during action implementation