import - Why ReadList ignores NullRecords for Number?

When thinking on this recent question the immediately obvious solution which came to my mind was to use ReadList with options RecordLists -> True and NullRecords -> True for reading objects of type Number. But I discovered that NullRecords -> True is ignored for Number although RecordLists -> True is respected:

ReadList[StringToStream["1 2 3\n4 5\n\n6 7\n8 9"], Number, RecordLists -> True, 
 NullRecords -> True]

{{1, 2, 3}, {4, 5}, {6, 7}, {8, 9}}

Currently the option NullRecords -> True is respected only for types Record and String:

ReadList[StringToStream["1 2 3\n4 5\n\n6 7\n8 9"], String, RecordLists -> True, 
 NullRecords -> True]

{{"1 2 3"}, {"4 5"}, {""}, {"6 7"}, {"8 9"}}

ReadList[StringToStream["1 2 3\n4 5\n\n6 7\n8 9"], Record, RecordLists -> True, 
 NullRecords -> True]

{{"1 2 3"}, {"4 5"}, {""}, {"6 7"}, {"8 9"}}

It is interesting that in version 5.2 this option was respected also for objects of type Word (but not for Number and Real):

$Version
ReadList[StringToStream["1 2 3\n4 5\n\n6 7\n8 9"], Word, RecordLists -> True,
  NullRecords -> True]

"5.2 for Microsoft Windows x86 (64 bit) (June 20, 2005)" 
{{"1", "2", "3"}, {"4", "5"}, {}, {"6", "7"}, {"8", "9"}}

The ignorance of NullRecords -> True for Number makes no sense for me, especially considering that RecordLists -> True is respected. Is there any reason for this? Is it a bug?

Comments

plotting - Plot 4D data with color as 4th dimension

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plotting - Filling between two spheres in SphericalPlot3D

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plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1....

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