At 32 bit float you just can't clip anything internally...
Look at this formula:
D =20⋅log ( 3,40⋅1038 ) ≈1530 dB dynamic range.............. 1,18⋅10−38
While the formula you gave is correct I prefer to use the term Absolute Range for this as there is a problem with resolution if you try to do that sort of thing on a mix bus. The resolution of 32 bit float is 25 bits (150dB) hence you would not be able to sum a signal at 0 dBFS to a signal at +1530 dBFS or even +200dBFS come to that as there is insufficient resolution in 32 bit float. It is therefore simpler (and more sensible) to suggest that all signals are kept below 0 dBFS when mixed such that the mix bus itself does not exceed 0 dBFS. The limited resolution is precisely why some DAW's offer 64 bit float accuracy which would otherwise be pointless.