Regulation 47 defines the rules on how time limits in public procurement may have to be extended from the minimum set in articles 27 to 31. As with Regulation 46 and lots, I believe that in general the obligation is to take into account circumstances that could potentially extend the time limits and that the decision remains in the contracting authority's sphere of discretion. Other than the specific cases from paragraphs 2 and 3, I do not believe that such obligation includes the actual extension of the time limits to receive tenders.
Paragraph 2 establishes a need for an extension in case the tender preparation is dependent on site inspection or "on-the-spot" document analysis ("shall be extended"). Both cases appear to trigger an automatic extension but the exact duration is not defined, thus leaving us to recourse to the general principles to do so, particularly proportionality. The way I read paragraph 4, which states the extension should be proportionate insofar as the importance of the information or change is that it is not applicable here and is relevant only for paragraph 3
Paragraph 3 states two different scenarios where time limits shall also be extended, although with the limitations of paragraph 4 (proportionality test) and 6 (significance). The first is when for whatever reason the information is provided only in the last 6 days of the deadline to submit tenders. As long as the information is not insignificant (more about that in a second), then the deadline needs to be extended in accordance with the proportionality test of paragraph 4. However, the proportionality test of paragraph 4 only checks the impartance of the missing information. Crucially it omits the issue of the contract complexity. It is bad enough that a variation of the principle of proportionality is mentioned here (it was not needed) and it is worse that it can mislead officials by thinking they have complied with the principle of proportionality even if they did not take into account the contract complexity to calculate the extension.
The second extension of paragraph 3 occurs when significant changes are made to the tender documents. The Regulation provides no guidance of what may constitute a significant change and I feel this can easily become a bone of contention. Perhaps the solution is an analogy to the material changes to the contract that trigger re-tendering?. I am thinking out loud here and would need to devote more time to this.
Another potential troublemaker is the definition of "insignificance" for the purposes of paragraph 6. Paragraph 6 excuses the contracting authority of providing the extension in case the information required is "insignificant". It is the contracting authority who needs to make this assessment but should do so in view with its importance to prepare the tenders. I suspect contracting authorities may feel tempted to define the information requested as insignificant often, as it allows them to keep to the original timeframe.