Are SPF 50 and SPF 100 chemical sunscreens meaningfully different?

Reviewers and dermatologists cited in coverage of La Roche-Posay Anthelios Melt-In Milk note that the jump from SPF 50 to SPF 100 offers a small absolute increase in UVB blocking but can be useful for very fair or photosensitive skin and for situations where reapplication is unrealistic.