...Soaking in the bowl is not indicative of the female being gravid. Soaking will occur for basically 3 reasons:
1) the female is trying to cool down (evaporative cooling)
2) the snake has mites
3) the snake just feels like soaking, lol!
In analysis,
1) An animal will resort to soaking to cool down primarily if it can't gain access to cooler air temps...
2) snakes instictively know that soaking will reduce external parasites...
3) Even desert species will soak from time-to-time if given the opportunity.
Some females will seek cooler temps prior to ovulation, but after ovulation, females will seek warmer temps (high 80's-low 90's). If the female is kept too warm AFTER ovulation, she may soak in an ATTEMPT at evaporative cooling. If a gravid female has access to temps between low 80's and low-mid 90's then soaking is usually secondary to relocation to a spot in the cage where temps suit the female's needs. I'd double-check your temps to make sure your conditions are correct.
One final point: Females do NOT gain weight during the pre-ovulation state or pregnancy UNLESS they are feeding. What may APPEAR to be weight gain is a redistribution of fat/protein from storage depots to the ova during pre-ovulation. Once ovulation occurs there is no more redistribution. Period. There WILL be exchange of respiratory gas (O2,CO2) only.
Good luck!
Scott J. Michaels DVM