Two experienced gardeners, one in Kuching and the other in Singapore, have told me that the name Bauhinia kockiana seems to have been applied to two different species. If there has been a mixup of identities, the only way to sort them out would be to compare the two plants against scientifically authenticated specimens in a herbarium.
The plant illustrated and described in Tropical Horticulture and Gardening is the one that is commonly grown in Malaysia and Singapore, but it only came into the market in the 1990s. It has become very popular because it flowers practically throughout the year.
The other plant is rare but seems to have come into cultivation much earlier. In Singapore, it flowers profusely once a year.