Hey Mr. Masterclass, what categories and how fast are IW and Miami?
According to a Plexipave article here
, the Plexipave IW surface is Category 1 Slow (24-29), but for some reason, according to the ITF tech surface pace list shown here
, Plexipave IW is Category 2 Medium Slow (30-34). Either way, remember that the base court pace can be altered via resurfacing to adjust the speed. Most players agree that this is one of the slowest hardcourts in the Masters series.
The Crandon Park courts are Laykold Cushion Plus MS which is rated by ITF (see link above) as Category 2 Medium Slow (30-34). It's generally considered a bit faster than Indian Wells, mainly because Indian Wells appears to have a higher bounce. Again, resurfacing of the basic surface can alter the speed/bounce somewhat. Also, as mentioned by others, weather can also affect the playing speed, so if high humidity is present in Miami, it could also slow down play.
I believe the tennis authorities should make it mandatory for tournaments to publicly display and record the surface court pace that has been tested using standardized testing methods by an accredited tester (non-tournament affiliated). For hardcourts or carpet, the frequency of testing could be once just prior to the start of a tournament (yearly), or at a minimum, following each resurfacing or replacement. Grass and clay are a bit more problematic as the surface can vary daily depending on conditions, so I think testing would need to be done yearly, ideally prior to and after the conclusion of the tournament (so one could get an average). Tournament results should also include the court pace rating in their statistics. From the ITF site, it appears that on-site accredited testing costs 500 dollars (US), so probably the expense of testing could be picked up by the tournament or from some shared pool of funds.