LP8720: PD value calculation

Part Number: LP8720

HI

Can I calculate the maximum current I can assume when all the LDO outputs of the LP8720 are assumed to be 1.8V?
Do I have to add up PD = (Vin-Vout) xIout for each channel like the original LDO calculation?
If so, can you check if my formula is correct?

Condition
VIN = 3.5V, VOUT = 1.8V, IOUT = 0.3A
R? JA = 45 ° C / W, TJ = 50 ° C

PD = (VIN - VOUT) x Iout
          (3.5-1.8) x 0.3 = 0.51
4ch LDO PD = PD x 4ch = 2.04

P = (TJ-TA) / R? JA
TA (MAX) = (PxR? JA) - TJ
                   = (2.04 x 45) - 150
                   = 58.2
In conclusion, design is possible at TA 58.2 ° C or less.
Is the above calculation correct? dcdc is not used.